December 7, 2009

Exhibit 10m.

PACCAR INC

LONG TERM INCENTIVE PLAN

2010 Form of Restricted Stock Award Agreement

This Restricted Stock Award Agreement (the “Agreement”), is entered into as of this      day of          (the “Award Date”) between PACCAR Inc, a Delaware corporation (the “Company”), and ( Key Employee) (the “Recipient”).

WHEREAS, The Company has established the PACCAR Inc Long Term Incentive Plan (the “LTIP”) in order to provide key employees of the Company and its subsidiaries with an opportunity to acquire shares of the Company’s common stock, par value $1 per share (the “Common Shares”); and

WHEREAS, the Compensation Committee of the Board of Directors charged with administering the LTIP (the “Committee”) has determined that it would be in the best interests of the Company and its stockholders to grant the Restricted Shares described in this Agreement to the Recipient as an inducement to enter into or remain in the service of the Company and as an incentive for extraordinary efforts during such service;

NOW, THEREFORE, in consideration of the mutual covenants herein contained, it is agreed as follows:

One-fourth shall vest on the first day of the month following certification of the performance goal, and an additional one-fourth on each succeeding first of January, so as to be 100% vested on January 1, (Insert Award Year + 3).

If the Recipient dies before the Company has distributed any vested Shares, the Company will distribute certificates to the beneficiary or beneficiaries the Recipient designated, in the proportions the Recipient specified. To be effective, a beneficiary designation must be made in writing and filed with the Company. If the Recipient failed to designate a beneficiary or beneficiaries, the Company will distribute certificates for the Common Shares to the Recipient’s surviving spouse or, if there is none, to his estate.

(Insert Award Year) Performance-Based Annual

Restricted Stock Award Agreement – Page 2

(Insert Award Year) Performance-Based Annual

Restricted Stock Award Agreement – Page 3

(Insert Award Year) Performance-Based Annual

Restricted Stock Award Agreement – Page 4

I agree to the terms and conditions of this restricted stock agreement

(Insert Award Year) Performance-Based Annual

Restricted Stock Award Agreement – Page 5

Exhibit 10p.

PACCAR INC SAVINGS INVESTMENT PLAN

Amendment and Restatement Effective January 1, 2009

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PACCAR INC SAVINGS INVESTMENT PLAN

(As Amended and Restated Effective January 1, 2009)

Effective January 1, 1955, Pacific Car and Foundry Company, the corporate predecessor of PACCAR Inc (a Delaware corporation), adopted the Pacific Car and Foundry Company Profit Sharing Plan and executed a Trust Agreement to provide profit-sharing benefits for its salaried employees

The Plan has been subsequently amended and restated and has been renamed the “PACCAR Inc Savings Investment Plan.” Effective April 1, 2005, PACCAR Inc amended and restated the Plan to provide that a portion of the Plan will constitute an employee stock ownership plan within the meaning of IRC section 4975(e)(7). Effective January 1, 2006, PACCAR Inc amended and restated the Plan to comply with final regulations under IRC section 401(k) and to make certain other amendments. Effective January 1, 2007, PACCAR Inc further amended and restated the Plan to incorporate amendments requested by the Internal Revenue Service in its October 23, 2008 determination letter for the Plan. Effective January 1, 2009, PACCAR Inc amended and restated the Plan to comply with the Pension Protection Act of 2006 and to make certain other amendments. Certain provisions, which are specifically identified, have a different effective date.

ARTICLE 1

PURPOSE AND SCOPE

The purposes of this amended and restated Plan are:

The Plan provides for contributions to be made by the Company to aid in accomplishing these purposes.

The Plan and the Trust Agreement are intended to meet the requirements of IRC sections 401(a), 401(k) and 501(a). The assets of the Plan are held in trust and are invested for the exclusive purpose of providing benefits to Members of the Plan and their Beneficiaries.

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The Plan is intended to qualify as an eligible individual account plan under section 407(d)(3) of ERISA, which is permitted to acquire and hold any amount of qualifying employer securities, and a portion of the Plan is intended to qualify as an employee stock ownership plan under IRC section 4975(e)(7), which portion is designed to invest primarily in PACCAR Stock.

The Plan, as set forth herein, applies to Members who are in employment as Employees on or after January 1, 2009. The rights and benefits, if any, of a former Employee shall be determined in accordance with the provisions of the Plan as in effect on the date when his employment terminated.

All acts required of the Company hereunder shall be performed by PACCAR Inc for itself and each of its participating Subsidiaries. The cost of the Plan shall be apportioned equitably among PACCAR Inc and its participating Subsidiaries; provided that if a Subsidiary is prevented from making any contribution which it otherwise would have made under the Plan by reason of having insufficient Current or Accumulated Earnings and Profits, then the contribution which such Subsidiary would have made shall be made by PACCAR Inc and its other participating Subsidiaries in such proportions as PACCAR Inc may determine, and in accordance with and subject to the deductible contribution limitations of IRC section 404 and the provisions of Article 5.

ARTICLE 2

DEFINITIONS AND CONSTRUCTION

The following words and phrases when used herein shall have the following meanings, unless the context otherwise requires:

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The term “Highly Compensated Employee” shall also include a former Employee who separated from service (or was deemed to have separated) prior to the determination year, performs no service for PACCAR Inc or any Subsidiary (as defined in Section 2.1(nn) without regard to the last sentence thereof) during the determination year, and was a Highly Compensated Employee as an active Employee for either the separation year or any determination year ending on or after the Employee’s 55th birthday.

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The determination of who is a Highly Compensated Employee, including the determinations of the number and identity of Employees in the Top-Paid Group, will be made in accordance with section 414(q) of the IRC and regulations thereunder.

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An Employee’s “Period of Service” shall commence on his Employment Date or Reemployment Date (as the case may be) and shall end when he quits, retires, is discharged, or dies. In determining whether an Employee has completed a 12-month Period of Service, the following rules shall apply:

In the case of an Employee who quit, retired or was discharged, his Period of Service shall include the period following such quit, retirement or discharge, if he is rehired as an Employee within 12 months after the date when he first became absent from active employment (whether by reason of such quit, retirement or discharge or for any other reason).

In the case of a reemployed Employee, all of his separate Periods of Service shall be aggregated and treated as a single continuous Period of Service. When partial months are aggregated, 30 days shall be deemed to equal one full month.

An Employee’s Period of Service shall be determined by the Company on the basis of employment records or on such other reasonable and nondiscriminatory basis as it may adopt. The Company, pursuant to written rules, may recognize as a Period of Service any period of time not otherwise described in this Section, subject to such conditions and limitations as it may adopt.

As used in this Section, the following words and phrases shall have the following meanings:

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Any definition of Section 414(s) Compensation shall be used consistently to define the compensation of all Employees taken into account in satisfying the requirements of an applicable provision of this Plan for the relevant determination period. Section 414(s) Compensation shall not include compensation paid to an Employee for a Plan Year in excess of $200,000 (as adjusted by the Commissioner of Internal Revenue to reflect increases in the cost-of-living in accordance with section 401(a)(17)(B)). For purposes of these limitations, if the Plan Year is less than 12 consecutive months, the limitation shall be prorated accordingly.

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Certain other defined terms used in particular provisions of the Plan are defined where used.

Any gender, where appearing in the Plan, shall be deemed to include the other gender, the singular shall include the plural, and the plural shall include the singular, unless the context otherwise requires. Titles are for reference only. In the event of a conflict between a title and the text of the Plan, the text of the Plan shall control. In the event of a conflict between the text of the Plan and any summary, description or other information regarding the Plan, the text of the Plan shall control.

ARTICLE 3

ELIGIBILITY AND MEMBERSHIP

Only an Eligible Employee may become a Member of the Plan. Any other individual is excluded from becoming a Member until such time as he becomes an Eligible Employee. An Eligible Employee may elect to become a Member as soon as reasonably practicable as of or after the date he has completed a 30-day Period of Service, provided that he is then an Eligible Employee. An Eligible Employee who does not elect to become a Member when he is first eligible to do so may elect to become such a Member at any time thereafter.

An Eligible Employee who wishes to become a Member shall apply for membership in such manner as specified under the Company’s written procedures. In filing an application for membership, an Eligible Employee shall agree to abide by the terms and conditions of the Plan and to provide such elections, designations or other information as the Company deems necessary for the proper administration of the Plan. An application to become a Member shall be implemented as soon as reasonably practicable after its receipt by the Company.

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An Eligible Employee, having become a Member, shall cease to be such a Member upon the termination of his employment as an Eligible Employee (although he will continue as a Restricted Member until the earlier of (a) his death or (b) the full distribution of any Benefit to which he is entitled under the Plan).

As long as any portion of the Benefit to which a Member is entitled under the Plan has not been distributed, such Member (while living) shall have the status of a Restricted Member for any period with respect to which:

An Employee (while living) shall also have the status of a Restricted Member if he is not a Member for all purposes of the Plan but has made a Rollover Contribution and such Contribution has not been fully distributed.

The following rules shall apply to Restricted Members and their Accounts with respect to periods during which they are Restricted Members:

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ARTICLE 4

SALARY DEFERRALS AND ROLLOVER CONTRIBUTIONS

Salary Deferrals are required of all Members other than Restricted Members. Subject to Section 4.15 and the limitations of this Article 4 and Article 15, any such Member may elect to contribute Salary Deferrals equal to any whole percentage of his Compensation received each pay period after becoming a Member, but not in excess of 35 percent of such Compensation. Salary Deferrals are not permitted to be made by a Member for any payday on which such Member is not an Eligible Employee.

The amount of a Member’s Salary Deferrals shall be withheld by the Company from his Compensation on each payday. All Salary Deferrals so withheld shall be paid by the Company to the Trustee as soon as reasonably practicable, but in no event later than the 15th day of the month next following the month in which they would otherwise have been payable to the Member in cash. Salary Deferrals shall be fully vested and nonforfeitable at all times.

For Federal income tax purposes (and, wherever permitted, for state and local tax purposes), Salary Deferrals shall be deemed to be employer contributions to the Plan, and a Member’s election to commence or continue his membership in the Plan shall constitute an election to have his taxable compensation reduced by the amount of all of his Salary Deferrals.

On or after February 1, 1983, no Member shall make any Member Contributions to the Plan. However, Member Contributions made before February 1, 1983, shall remain credited to the Member’s Employee Accounts until they are withdrawn or distributed pursuant to the provisions of the Plan.

At any time prior to or during a Plan Year, the Company (at its sole discretion) may reduce the maximum rate at which any Member may contribute Salary Deferrals to the Plan for such Plan Year or during the remainder of such Plan Year, or the Company may require that any Member discontinue all Salary Deferrals for the remainder of such Plan Year, for the purpose of meeting the special nondiscrimination rules under the IRC. Any reduction or discontinuance of Salary Deferrals may be applied selectively to individual Members or to particular classes of Members, as the Company may determine. In addition to requiring a prospective reduction or discontinuance of Salary Deferrals, the Company may distribute to any Member such portion of the Salary Deferrals that he already contributed for a Plan Year as it determines is necessary to meet the special nondiscrimination rules under the IRC for such year, as provided in Sections 4.5, 4.9 and 15.3 below.

A Member may elect at any time to change the rate of his Salary Deferrals prospectively to any other percentage permitted under this Article 4. Any election pursuant to this Section 4.3 shall be made in accordance with the Company’s written procedures applicable at the time of the election.

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A Member may elect to suspend all Salary Deferrals at any time, thereby becoming a Restricted Member pursuant to Section 3.4. Any such election shall be made in accordance with the Company’s written procedures. Any election to resume Salary Deferrals shall become effective as soon as reasonably practical after it is received by the Company, but in no event earlier than 90 days after the effective date of the election to suspend Salary Deferrals.

When a Member resumes Salary Deferrals following such suspension, he may make new elections under this Article 4 regarding the amount and allocation thereof; provided, however, that if he does not make such new elections, his previous elections shall be applicable.

Subject to Section 4.15, the aggregate Salary Deferrals of any Member for any calendar year, together with his or her elective deferrals under any other plan or arrangement to which section 402(g) of the IRC applies and that is maintained by PACCAR Inc or any Subsidiary (as defined in Section 2.1(nn) without regard to the last sentence thereof), shall not exceed $15,000 (or such larger amount as may be adopted by the Commissioner of Internal Revenue to reflect a cost-of-living adjustment). In the event that such aggregate Salary Deferrals and elective deferrals of any Member for any calendar year exceed $15,000 (or such larger amount as may be adopted by the Commissioner of Internal Revenue to reflect a cost-of-living adjustment), then such portion of the Excess Deferrals, and any income or loss allocable to such portion for the calendar year (but not for the period between the end of the calendar year and the date of distribution of such Excess Deferrals) shall be refunded to the Member not later than the April 15 next following the close of such calendar year. Such income (and loss) allocable to Excess Deferrals shall be determined in accordance with Treasury Regulation section 1.402(g)-1(e)(5).

In the event that a Member’s elective deferrals (within the meaning of section 402(g)(3) of the IRC) for a calendar year exceed $15,000 (or such larger amount as may be adopted by the Commissioner of Internal Revenue to reflect a cost-of-living adjustment) solely because such Member participated in this Plan and a plan or arrangement maintained by an employer other than PACCAR Inc or any Subsidiary (as defined in Section 2.1(nn) without regard to the last sentence thereof), then such Member may designate all or a portion of such Excess Deferrals as attributable to this Plan and may request a refund of such portion by notifying the Company in writing on or before the March 1 next following the close of such calendar year. If timely notice is received, then such a Member’s Excess Deferrals, and any income or loss allocable thereto, shall be refunded to the Member from this Plan no later than the April 15 next following the close of such calendar year.

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The Plan shall satisfy the average deferral percentage test provided in section 401(k)(3) of the IRC and section 1.401(k)-1 of the Income Tax Regulations issued thereunder. Subject to the special rules described in Section 4.11, the Aggregate 401(k) Contributions of Highly Compensated Employees shall not exceed the limits described below:

The maximum Actual Deferral Percentage shall be determined by use of a leveling process, whereby the Aggregate 401(k) Contributions of the Highly Compensated Employee with the highest Actual Deferral Percentage are reduced to the extent required to (a) eliminate all Excess Contributions or (b) cause such Highly Compensated Employee’s Actual Deferral Percentage to equal the Actual Deferral Percentage of the Highly Compensated Employee with the next-highest Actual Deferral Percentage. Such leveling process shall be repeated until the average deferral percentage test is satisfied.

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With regard to each Highly Compensated Employee whose Actual Deferral Percentage is in excess of the maximum permitted Actual Deferral Percentage, a dollar amount of Excess Contributions shall then be determined by subtracting the product of the maximum permitted Actual Deferral Percentage and the Highly Compensated Employee’s Section 414(s) Compensation from the Highly Compensated Employee’s Aggregate 401(k) Contributions. The amounts shall then be aggregated to determine the total dollar amount of Excess Contributions.

Any Excess Contributions for a Plan Year shall be allocated to Highly Compensated Employees by use of a leveling process, whereby the Aggregate 401(k) Contributions of the Highly Compensated Employee with the highest dollar amount of Aggregate 401(k) Contributions are reduced to the extent required to (a) eliminate all Excess Contributions or (b) cause such Highly Compensated Employee’s Aggregate 401(k) Contributions to equal the Aggregate 401(k) Contributions of the Highly Compensated Employee with the next-highest Aggregate 401(k) Contributions. Such leveling process shall be repeated until all Excess Contributions for such Plan Year are allocated to Highly Compensated Employees.

Effective for Plan Years beginning on or after January 1, 2008, Excess Contributions allocated to Highly Compensated Employees for the Plan Year pursuant to Section 4.8, together with any income or loss allocable to such Excess Contributions for the Plan Year (but not for the period between the end of the Plan Year and the date of distribution of such Excess Contributions) shall be distributed to such Highly Compensated Employees not later than the March 15 next following the close of such Plan Year, if possible, and in any event no later than 12 months following the close of such Plan Year. Such income (and loss) allocable to Excess Contributions shall be determined in accordance with Treasury Regulation section 1.401(k)-2(b)(2)(iv). Any Salary Deferrals distributed pursuant to this Section 4.9 shall not be included in the Salary Deferrals that attract a Company Contribution under Section 5.2. Notwithstanding the foregoing, to the extent Excess Contributions allocated to a Highly Compensated Employee for the Plan Year pursuant to Section 4.8 could otherwise constitute Age 50 Catch-Up Deferrals pursuant to Section 4.15, such Excess Contributions shall be recharacterized as Age 50 Catch-Up Deferrals for the Plan Year rather than be distributed to the Highly Compensated Employee as described above.

The Company, in its sole discretion, may include all or a portion of the Company Contributions for a Plan Year in Aggregate 401(k) Contributions taken into account in applying the Average Deferral Percentage limitation described in Section 4.6 for such Plan Year, provided that the requirements of section 1.401(k)-2(a)(6) of the Income Tax Regulations are satisfied.

The following special rules shall apply for purposes of this Article 4:

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A Member shall elect to allocate his Salary Deferrals among the Investment Options designated by the Company. Each Eligible Employee shall elect, when he enrolls in the Plan, to allocate Salary Deferrals to one or more Investment Options in any whole percentage increment. A Member who is an Employee may elect to change the relative amounts of future Salary Deferrals being allocated to one or more Investment Options in any whole percentage increment.

Any Member may elect to transfer any whole percentage of the amount of the Member’s Salary Deferral Account or Employee Account then invested in one Investment Option to another Investment Option as permitted by the Company’s written procedures.

An election under this Section 4.13 may be made at any time to be effective as soon as reasonably practicable after it is received by the Company. Any election under this Section 4.13 shall be made in accordance with the Company’s written procedures.

With the Company’s prior written approval, any Eligible Employee may make one or more Rollover Contributions to the Plan. An Eligible Employee who makes a Rollover Contribution at a time when he or she is not a Member for other purposes shall become a Restricted Member. A Rollover Contribution shall be permitted only if it meets all of the following conditions:

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A Rollover Contribution shall be paid to the Company in a lump sum in cash. Each approved Rollover Contribution shall be transferred to the Trustee as soon as reasonably practicable after it was paid to the Company. The Rollover Contribution shall be allocated among one or more Investment Options in any whole percentage increment as the Member may elect. Such election shall be made in accordance with the Company’s written procedures.

Eligible Members (as defined in Section 4.15(a) below) may make additional Salary Deferrals (“Age 50 Catch-Up Deferrals”) up to the amounts specified in Section 4.15(b) below.

Age 50 Catch-Up Deferrals made pursuant to this Section 4.15 shall not be taken into account for purposes of the provisions of the Plan implementing the limitations of section 402(g) and section 415 of the IRC. The Plan shall not be treated as failing to satisfy the provisions of the Plan implementing the requirements of sections 401(k)(3), 401(k)(11), 401(k)(12), 410(b) or 416 of the IRC by reason of such Age 50 Catch-Up Deferrals.

ARTICLE 5

COMPANY CONTRIBUTIONS

The Company may, in its sole discretion, make one or more Company Contributions during each Plan Year with respect to Members’ Salary Deferrals (other than Age 50 Catch-Up Deferrals). The Company’s rate of contribution and the frequency and manner in which the

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Company makes its contribution shall be decided by the Company in its sole discretion with respect to each Plan Year. Company Contributions initially may be paid to a suspense account maintained by the Trustee as part of the Plan. The aggregate amount of Company Contributions for each Plan Year shall be equal to the sum of the amounts allocated for such Plan Year to Members pursuant to Section 5.2. Company Contributions may be made in the form of PACCAR Stock. Company Contributions shall be paid to the Trustee as soon as practicable following the end of the period for which the contributions are being made, but shall in no event be paid to the Trustee later than the due date for filing the Company’s federal income tax return (including extensions) for the Plan Year.

Company Contributions, determined under Section 5.1, shall be allocated as of the last day of each Plan Year to the Company Contributions Account of each Member who has completed a 12-month Period of Service on or before the last day of such Plan Year and who is an Employee on such date or who terminated employment during such Plan Year due to:

if the Member defers distribution of his Plan Benefit to a date later than the last day of the Plan Year in which he separates from service.

The allocation shall be in an amount equal to the lesser of (1) a percentage, to be determined each Plan Year in the Company’s sole discretion, of the aggregate Salary Deferrals (other than Age 50 Catch-Up Deferrals) made by each eligible Member during the Plan Year, not including Salary Deferrals returned to the Member pursuant to Sections 4.5, 4.9 or 15.3, or (2) a percentage, to be determined each Plan Year in the Company’s sole discretion, of Compensation received during the portion of the Plan Year that the eligible Member is an Eligible Employee and a Member (including a Restricted Member) and has completed a 12-month Period of Service (in the current or a prior Plan Year). Company Contributions may be allocated in the form of PACCAR Stock which shall be valued for allocation purposes on the basis of the average price per share of all shares of PACCAR Stock paid to the Plan as part of the Company Contributions and acquired with suspense-account funds during the Plan Year pursuant to Section 5.1.

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The Plan shall satisfy the average contribution percentage test provided in section 401(m)(2) of the IRC and section 1.401(m)-1 of the regulations issued thereunder. Subject to the special rules described in Section 5.8, the Aggregate 401(m) Contributions of Highly Compensated Employees shall not exceed the limits described below:

The maximum Actual Contribution Percentage shall be determined by use of a leveling process, whereby the Aggregate 401(m) Contributions of the Highly Compensated Employee with the highest Actual Contribution Percentage are reduced to the extent required to (a) eliminate all Excess Aggregate Contributions or (b) cause such Highly Compensated Employee’s Actual Contribution Percentage to equal the Actual Contribution Percentage of the Highly Compensated Employee with the next-highest Actual Contribution Percentage. Such leveling process shall be repeated until the average contribution percentage test is satisfied.

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With regard to each Highly Compensated Employee whose Actual Contribution Percentage is in excess of the maximum permitted Actual Contribution Percentage, a dollar amount of Excess Aggregate Contributions shall then be determined by subtracting the product of the maximum permitted Actual Contribution Percentage and the Highly Compensated Employee’s Section 414(s) Compensation from the Highly Compensated Employee’s Aggregate 401(m) Contributions. The amounts shall then be aggregated to determine the total dollar amount of Excess Aggregate Contributions.

Any Excess Aggregate Contributions for a Plan Year shall be allocated to Highly Compensated Employees by use of a leveling process, whereby the Aggregate 401(m) Contributions of the Highly Compensated Employee with the highest Aggregate 401(m) Contributions are reduced to the extent required to (a) eliminate all Excess Aggregate Contributions or (b) cause such Highly Compensated Employee’s Aggregate 401(m) Contributions to equal the Aggregate 401(m) Contributions of the Highly Compensated Employee with the next-highest Aggregate 401(m) Contributions. Such leveling process shall be repeated until all Excess Aggregate Contributions for such Plan Year are allocated to Highly Compensated Employees.

Effective for Plan Years beginning on or after January 1, 2008, Excess Aggregate Contributions allocated to Highly Compensated Employees for the Plan Year pursuant to Section 5.5, together with any income or loss allocable to such Excess Aggregate Contributions for the Plan Year (but not for the period between the end of the Plan Year and the date of distribution of such Excess Aggregate Contributions) shall be distributed to such Highly Compensated Employees not later than the March 15 next following the close of such Plan Year, if possible, and in any event no later than 12 months following the close of such Plan Year. Such income (and loss) allocable to Excess Aggregate Contributions shall be determined in accordance with Treasury Regulation section 1.401(m)-2(b)(2)(iv).

The Company, in its sole discretion, may include all or a portion of the Salary Deferrals (other than Age 50 Catch-Up Deferrals) for a Plan Year in Aggregate 401(m) Contributions taken into account in applying the Average Contribution Percentage limitation described in Section 5.3 for such Plan Year, provided that the requirements of section 1.401(m)-2(b)(6) of the Income Tax Regulations are satisfied.

The following special rules shall apply for purposes of this Article 5:

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The Company may elect to pay all or part of any Company Contribution in the form of PACCAR Stock. For purposes of determining the amount of the Company’s deduction under section 404 of the IRC, shares of PACCAR Stock so contributed shall be valued at the last-transaction price quoted by the National Market System of the National Association of Securities Dealers and reported by The Wall Street Journal with respect to the date on which such shares are paid to the Plan.

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Each Member who has completed three or more years of service (as defined below) may elect at any time to transfer any whole percentage of the amount of the Member’s Company Contributions Account then invested in one Investment Option (including the PACCAR Stock Fund) to another Investment Option (including the PACCAR Stock Fund) in accordance with the Company’s written procedures. Any future Company Contributions allocated to such Member may, in the Company’s sole discretion, continue to be allocated to the Member’s Company Contributions Account in the form of PACCAR Stock.

The Beneficiary of a deceased Member (whether or not the Member has completed three or more years of service) shall have the same investment rights as herein described.

For purposes of this Section 5.10, the date on which a Member completes three years of service is the third anniversary of the Member’s date of hire.

Any other provision of the Plan notwithstanding, each Company Contribution under Section 5.1 is expressly conditioned upon the deductibility of such contribution under Section 404 of the IRC. If the deductibility of a Company Contribution is denied, then the amount for which a deduction is disallowed (reduced by any losses incurred with respect to such amount) shall be returned to the Company within 12 months after the date of the disallowance. In addition, if all or part of a Company Contribution is attributable to a mistake of fact, then the excess of such Company Contribution over the amount which would have been contributed in the absence of the mistake of fact (reduced by any losses incurred with respect to such excess) shall be returned to the Company within 12 months after the date of such Company Contribution.

ARTICLE 6

THE TRUSTEE AND THE TRUST FUND

The exclusive authority and discretion to manage and control the Trust Fund shall be vested in the Trustee, except to the extent that the Trust Agreement provides that the Trustee is subject to the directions of the Company or an Investment Manager appointed by the Company. Accordingly, subject to the provisions of the Plan, the Company shall enter into one or more Trust Agreements in such form and containing such provisions as the Company may deem appropriate, including (without limitation) constraints on the investment of the Trust Fund and the power and authority of the Trustee to amend the Trust Agreement or to terminate the trust. All Salary Deferrals, Rollover Contributions and Company Contributions under the Plan shall be paid by the Company to the Trustee to be held, invested and distributed subject to the terms and conditions of the Plan and the Trust Agreement.

The Company from time to time may appoint one or more Investment Managers with respect to all or any portion of the Trust Fund and may enter into an investment

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management agreement with any Investment Manager so appointed. Each Investment Manager so appointed shall have the exclusive authority and discretion to manage and control the assets of the Trust Fund assigned to him (it), except to the extent that the applicable investment management agreement provides that such Investment Manager is subject to the directions of the Company or a Trustee.

The Trust Fund shall consist of the PACCAR Stock Fund and one or more Investment Options selected by the Company. For purposes of investment, the Trustee may divide any part of the Trust Fund into one or more sub-funds. The Trustee may physically segregate the assets of any sub-fund, invest the assets of such sub-fund separately, and account separately for the income, gains, expenses and losses of such sub-fund.

The “PACCAR Stock Fund” shall be invested in PACCAR Stock. The PACCAR Stock Fund shall consist of all PACCAR Stock held by the Trustee, and all cash held by the Trustee which is derived from dividends on PACCAR Stock, Company Contributions to be invested in PACCAR Stock, Salary Deferrals by Members that are to be invested in PACCAR Stock, Member Contributions that are to be invested in PACCAR Stock, Rollover Contributions that are to be invested in PACCAR Stock, and proceeds from sales of PACCAR Stock (except while such cash may be otherwise invested as provided under the Trust Agreement). All dividends on PACCAR Stock and all proceeds from the sale of PACCAR Stock shall be invested in the PACCAR Stock Fund, except as otherwise provided in the Plan.

Trust Fund assets invested in PACCAR Stock may be registered in the name of the Trustee or any nominee; provided that the Trustee’s records evidence the interest of the Trust Fund therein. Each Member shall be entitled to vote the whole number of shares of PACCAR Stock credited to him in his Company Contributions Account, Salary Deferral Account, and Employee Account as of the most recent practicable Valuation Date prior to the record date for each meeting of shareholders of PACCAR Inc. Each Member, prior to such meeting, shall be furnished with the proxy statement for such meeting, together with a form to be sent to the Trustee on which may be set forth the Member’s instructions as to the manner of voting such shares of PACCAR Stock. Upon receipt of such instructions (which the Trustee shall hold in confidence), the Trustee shall vote such shares in accordance therewith. The Trustee shall vote all shares of PACCAR Stock held by it upon any matter as to which no instructions were given by Members within such reasonable period of time prior to any shareholder meeting as may be specified by the Trustee, or which cannot be voted pursuant to Members’ instructions, in direct proportion to the shares of PACCAR Stock with respect to which it has received timely voting instructions by Members.

In the event that any person or group of persons makes a tender offer subject to section 14(d) of the Securities Exchange Act of 1934 to acquire all or part of the outstanding shares of PACCAR Stock, including the PACCAR Stock held in the Trust Fund

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(“Acquisition Offer”), each Member shall be entitled to direct the Trustee confidentially to tender all or part of those shares of PACCAR Stock that would then be subject to such Member’s voting instructions under Section 6.3. If the Trustee receives an instruction by the date communicated by the Company to Members, the Trustee shall tender such shares in accordance with such instruction. Any PACCAR Stock as to which the Trustee does not receive timely instructions shall not be tendered by the Trustee. The Company shall distribute to each Member all appropriate materials pertaining to the Acquisition Offer, including the statement of the position of the Company with respect to such offer issued pursuant to Rule 14e-2 under the Securities Exchange Act of 1934, as soon as practicable after such materials are issued; provided, however, that if the Company fails to issue such statement within five business days after the commencement of such offer, the Company shall distribute such materials to each Member without the statement by the Company and shall separately distribute such statement as soon as practicable after it is issued.

All payments of Benefits shall be made solely from the assets of the Trust Fund. No Fiduciary guarantees the Trust Fund or any Company Contributions, Salary Deferrals, Rollover Contributions or Member Contributions in any manner against investment loss or depreciation in asset value. Except only as expressly provided by the Plan, and then only to the extent of his Benefit payable under the Plan from the assets of the Trust Fund, no person shall have any right to, or interest in, any assets of the Trust Fund.

The Plan is intended to comply with section 404(c) of ERISA with respect to Salary Deferral Accounts. Accordingly, with respect to the investment of such Accounts, the Plan shall satisfy, among other requirements, Subsections (a), (b) and (c) below.

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Information that must be provided on request in accordance with Department of Labor Regulation 2550.404c-1(b)(2) includes certain information relating to financial reports of Investment Options, operating expenses of the portfolio assets of the Investment Options, overall investment performance of the Investment Options and information relating to the shares of an investment in the requesting Members’ Account. Additional information may be available upon request.

The Beneficiary of a Member shall have the same investment rights as herein described where such Beneficiary becomes entitled to a Member’s Salary Deferral Account under the Plan.

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The fees of the Trustee and any Investment Manager, and the expenses of administering the Trust Fund and the Plan, shall be paid by the Trustee out of the Trust Fund pursuant to the terms of the Trust Agreement, except such expenses as are paid by the Company.

ARTICLE 7

ACCOUNTS AND VALUATIONS

The Company shall establish and maintain Accounts for each Member which reflect his interest in contributions made under the Plan and the investment experience thereof. A Member’s interest in the Plan shall consist of one or more of the following Accounts:

A Company Contributions Account, reflecting Company Contributions made on behalf of a Member with respect to periods after June 30, 1978 and earnings, losses and expenses attributable to such Company Contributions.

A Salary Deferral Account, reflecting Salary Deferrals (including Age 50 Catch-Up Deferrals) and Rollover Contributions made by a Member to the Plan and earnings, losses and expenses attributable to such Salary Deferrals (including Age 50 Catch-Up Deferrals) and Rollover Contributions. A Salary Deferral Account may also include amounts transferred from a Prior Profit Sharing Account effective July 1, 1987, and earnings, losses and expenses attributable to such amounts.

An Employee Account, reflecting Member Contributions made by a Member to the Plan prior to February 1, 1983 and earnings, losses and expenses attributable to such Member Contributions.

Such separate Accounts are maintained for accounting purposes and shall not require a segregation of Trust Fund assets to each Account.

As of each Valuation Date, the Company shall determine the fair market value and balance of each Member’s Accounts, as provided in (a), (b), (c) and (d) below. The Company may use any lawful procedure for determining the fair market value and balance of Accounts; provided that such procedure is consistent with this Section 7.2.

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The Company shall ascertain from the Trustee the fair market value of the assets of each portion of the Trust Fund as of the valuation Date. The fair market value of PACCAR Stock shall be the last-transaction price quoted by the National Market System of the National Association of Securities Dealers and reported by The Wall Street Journal with respect to the Valuation Date.

The Company shall credit to each Member’s Company Contributions Account the amount of any Company Contributions allocated as of a day or days within the Plan Year as the Company shall determine in its sole discretion. The Company shall credit to each Member’s Salary Deferral Accounts the amount of Salary Deferrals withheld, transfers from Company Contributions Accounts received and Rollover Contributions received in such calendar month.

The Company shall charge against each Member’s Company Contributions, Salary Deferral and Employee Accounts, as applicable, the amount of any transfers, withdrawals, loans and distributions of Benefits effected during the calendar month ending with the Valuation Date.

Notwithstanding any other provision of the Plan, a Member may, in accordance with procedures established by the Company, elect to have any cash dividends paid on PACCAR Stock that is held in the Member’s Company Contributions Account, Salary Deferral Account or Employee Account, as applicable, paid directly to such Member in cash or allocated to the Member’s Account(s) and re-invested in PACCAR Stock. In the absence of a proper election by the Member, any such cash dividend shall be allocated to the Member’s Account(s) and re-invested in PACCAR Stock.

A statement for each Member shall be prepared and distributed to the Member annually or more frequently, as determined by the Company. Such statement shall reflect the status (including the fair market value) of the Member’s Accounts and shall contain such other information as the Company may determine.

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ARTICLE 8

AMOUNT AND DISTRIBUTION OF BENEFITS

Each Member’s interest in his Accounts is 100 percent vested at all times. In the case of a reemployed Member who previously incurred a forfeiture from his Company Contributions Account under the Plan as in effect prior to January 1, 1989, any such forfeiture may be restored to the Member’s Company Contributions Account if the Member satisfies the requirements of the Plan as in effect prior to January 1, 1989, concerning the repayment of prior forfeitures. Benefits to which a Member is entitled are distributable to such Member or his Beneficiary, as the case may be, as further provided in this Article 8. The amount distributable to the Member shall be determined as of the later of (a) the Valuation Date coinciding with or immediately following the date of the Member’s termination of employment or (b) the Valuation Date coinciding with or immediately preceding the distribution date elected by the Member under Section 8.2.

Subject to Sections 8.3, 8.4 and 8.8, a Member’s Benefit shall be distributed to him on (or as soon as reasonably practicable after) the date that he has elected. The distribution election shall be made in accordance with the Company’s written procedures, and where applicable, such procedures shall require the consent (written, if necessary) of the Member to the distribution of his Benefit before he attains age 65.

A Member who is Totally Disabled may elect to receive his Plan Benefit in accordance with the Company’s written procedures. In the case of a Member who is not Totally Disabled, the Benefit shall not be distributed before the later of the following dates:

Notwithstanding the preceding provisions of this Section 8.3 and subject to Section 8.4, a Member’s Benefit shall be paid or commenced by his Required Beginning Date. If the Member fails to file a timely distribution election form, Section 8.7 shall apply and Section 8.12 (relating to unclaimed Benefits) may apply.

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In the event that a Member is reemployed and becomes a Member of the Plan prior to the distribution of his entire Benefit relating to his earlier period of employment, then (a) any election of a deferred distribution date under Section 8.2 shall be disregarded; (b) any installment payments in process shall be discontinued, and the undistributed portion of the Member’s Accounts which formerly had been in his PACCAR Stock Fund (if any) shall be retransferred to his PACCAR Stock Fund; and (c) the Member’s entire Benefit, including the Benefit relating to the period following his reemployment, shall be distributed in accordance with the latest distribution election form filed by the Member, after his reemployment, pursuant to Section 8.2.

A Member whose employment as an Employee terminates may elect to have his Benefit distributed in one of the following forms:

A Member entitled to a Benefit shall elect a form of distribution under Section 8.6 in accordance with the Company’s written procedures. Such election shall include such information as the Company may reasonably require and, if the distribution is to be made prior to the Member’s attainment of age 65, the election shall be made no more than 90 days (180 days with respect to distributions made on or after January 1, 2010) prior to the distribution date elected by the Member.

If a Member’s Benefit must be paid after he ceases to be an Employee on account of his Required Beginning Date, he shall elect a form of distribution under Section 8.6

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for this Benefit. If the Member fails to elect any form of distribution for such benefit before his Required Beginning Date, then such Benefit shall be distributed in the form of a lump sum consisting entirely of cash.

Any other provision of this Article 8 notwithstanding, effective for distributions made on or after March 28, 2005, if the value of a Member’s entire Benefit equals $1,000 or less before the first payment of such Benefit is made, then the Benefit automatically shall be paid to such Member (or, in the case of his termination as a result of his death, to his Beneficiary) in a single lump sum in cash as soon as administratively practicable after the Member’s termination and without his consent. The foregoing notwithstanding, (a) in the case of a Member who has made the election described in Section 5.2, the determination of whether the value of the Member’s entire Benefit equals $1,000 or less shall be made immediately following the last day of the Plan Year in which such Member terminated employment and (b) in the event of termination of a Member’s employment due to a Layoff, payment shall be made as soon as administratively practicable following the last day of the Plan Year following the Plan Year in which the termination of employment occurred. If the value of a benefit payable to an alternate payee pursuant to a qualified domestic relations order (as defined in section 414(p) of the IRC) (“QDRO”) is not more than $1,000 and payment of such benefit has not commenced, such benefit shall be paid automatically to such alternate payee in a single lump sum in cash as soon as administratively practicable after the QDRO is received by the Plan and without the alternate payee’s consent.

This Subsection (a) shall apply only in the event that a Member elected to receive all or a portion of his Benefit in annual installments (previously available under the Plan with respect to distributions commencing prior to May 1, 2003), and then dies after installment payments have commenced but before such payments are completed. Such Member’s Benefit ordinarily shall be paid to his Beneficiary in the form of a single lump sum in cash, and the distribution ordinarily shall be made as soon as reasonably practicable after the Member’s death. A Beneficiary may, however, make request to defer the distribution of the Benefit to which such Beneficiary is entitled. However, the distribution shall in no event be made later than five years after the Member’s death. A Beneficiary shall make the request to receive the Benefit to which such Beneficiary is entitled or to defer receipt in accordance with the Company’s written procedures.

Upon commencement of membership, each Member shall name one or more persons as the Beneficiary who will receive any distribution payable under the Plan in the event of the Member’s death. The designation shall be registered with the Company in accordance with the Company’s written procedures. If the Member has not made an effective designation of a Beneficiary or if none of the named

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Beneficiaries is living when any distribution is to be made, then (1) the spouse of the deceased Member shall be the Beneficiary or (2) if the Member has no spouse living at the time of such distribution, then the living children of the deceased Member shall be the Beneficiaries in equal shares or (3) if the Member has neither spouse nor children living at the time of such payment, the estate of the Member shall be the Beneficiary. The Member may change his designation of a Beneficiary from time to time in accordance with procedures established by the Company. Any other provision of this Subsection (b) notwithstanding, in the case of a married Member, any designation of a person other than his spouse as Beneficiary shall be effective only if the spouse consents to the designation in writing and such written consent is witnessed by a notary public.

No benefit payable under the Plan shall be subject in any manner to anticipation, alienation, sale, transfer, assignment, pledge, encumbrance, charge, garnishment, execution or levy of any kind, either voluntary or involuntary, prior to actually being received by the person entitled to such benefit under the terms of the Plan; and any attempt to anticipate, alienate, sell, transfer, assign, pledge, encumber, charge or otherwise dispose of any right to a benefit payable hereunder shall be void. However, neither of the following shall constitute a violation of this Section 8.10:

Pursuant to a qualified domestic relations order, the Plan may distribute any benefit payable to an alternate payee in the form of a single lump sum in cash prior to the earliest date upon which the Member could receive his Benefit. To the extent that a qualified domestic relations order creates, assigns, or recognizes the right of an alternate payee to any portion of the Benefit otherwise payable to or with respect to a Member, such portion shall not thereafter be taken into account in determining the Benefit payable to or with respect to that Member under the Plan.

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Whenever, in the Company’s opinion, a person entitled to receive any distribution of a Benefit or installment thereof is under a legal disability or is physically or mentally incapacitated in any way so as to be unable to manage his financial affairs, the Company may direct the Trustee to make distribution to such person or to his legal representative or to a relative or friend of such person for his benefit; or the Company may direct the Trustee to apply the payment for the benefit of such person in such manner as the Company considers advisable.

If any Benefit, or a portion thereof, becomes distributable under the Plan and the Company is unable to locate the Member or Beneficiary to whom the distribution is payable for three consecutive Plan Years, then the Member’s Accounts shall be closed after the third consecutive Plan Year during which such distribution is payable but the Member or Beneficiary cannot be found. The amount of the unpaid Benefit shall be applied to reduce Company Contributions (unless mandatory provisions of applicable escheat laws require other application, in which case such Benefit shall be applied as such mandatory laws require), as determined by the Company. If, however, the Member or Beneficiary subsequently makes a proper claim to the Company for any Benefit applied to reduce Company Contributions, then such Benefit (without income, gains or other adjustment) shall be restored to the Member’s Accounts from contributions made by the Company for this purpose, without regard to Current or Accumulated Earnings and Profits. The Benefit shall thereafter be distributable in accordance with the terms of the Plan.

Any payment or distribution made to any person in full compliance with the terms of the Plan shall fully discharge the Company, the Plan and any Trustee or insurance company making such payment from all adverse claims thereto respecting which prior written notice has not been given to any such entity making or directing the payment or distribution. If the Company has received actual written notice of any adverse claim to any payment or distribution not yet made, the Company may suspend distribution and take such other action as it deems necessary or advisable to protect the Plan or its Members and Beneficiaries, until the respective rights of all interested persons have been determined to the satisfaction of the Company.

Notwithstanding any provision of the Plan to the contrary that would otherwise limit a Distributee’s election under this Section, a Distributee may elect, at the time and in the manner prescribed by the Company, to have any portion of an Eligible Rollover Distribution paid directly to an Eligible Retirement Plan specified by the Distributee in a Direct Rollover.

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Effective with respect to distributions made after December 31, 2006, an Eligible Rollover Distribution is any distribution of all or any portion of the balance to the credit of the Distributee, except that an Eligible Rollover Distribution does not include: any distribution that is one of a series of substantially equal periodic payments (not less frequently than annually) made for the life (or life expectancy) of the Distributee or the joint lives (or joint life expectancies) of the Distributee and the Distributee’s designated beneficiary, or for a specified period of 10 years or more; any distribution to the extent such distribution is required under section 401(a)(9) of the IRC; the portion of any distribution that is not includable in gross income (determined without regard to the exclusion for net unrealized appreciation with respect to employer securities), except to the extent that such portion is directly rolled over to a qualified trust described in section 401(a) of the IRC, or an annuity contract described in section 403(b) of the IRC, which agrees to separately account for the portion which is not so includible, or such portion is rolled over to an individual retirement account or annuity described in section 408(a) or 408(b) of the IRC; and a distribution which is made upon hardship of the Distributee.

Effective with respect to an Eligible Rollover Distribution made after December 31, 2006, an Eligible Retirement Plan is an individual retirement account described in section 408(a) of the IRC; an individual retirement annuity described in section 408(b) of the IRC; an annuity plan described in section 403(a) of the IRC; an annuity contract described in Section 403(b) of the IRC; an eligible plan under Section 457(b) of the IRC maintained by a state, political subdivision of a state, or any agency or instrumentality of a state or political subdivision of a state, that agrees to account separately for the Eligible Rollover Distribution; or a qualified trust described in section 401(a) of the IRC that accepts the Distributee’s Eligible Rollover Distribution. With respect to the portion of an Eligible Rollover Distribution that is not includible in gross income (if it were paid to the Distributee), an “Eligible Retirement Plan” is limited to a qualified trust described in section 401(a) of the IRC, or an annuity contract described in section 403(b) of the IRC, that agrees to account separately for the portion which is includible in gross income and the portion which is not so includible, or an individual retirement account or annuity described in section 408(a) or 408(b) of the IRC. Effective with respect to an Eligible Rollover Distribution made on or after July 1, 2007 to a Beneficiary who is not the Employee’s or former Employee’s surviving spouse, an “Eligible Retirement Plan” is limited to an individual retirement account or annuity described in section 408(a) or 408(b) of the IRC established for the purpose of receiving the Eligible Rollover Distribution on behalf of such Beneficiary and that agrees to be treated as an inherited individual retirement account or annuity within the meaning of section 402(c)(11) of the IRC. Effective with respect to an Eligible Rollover Distribution made after December 31, 2007, “Eligible Retirement Plan” also includes a Roth IRA described in section 408A of the IRC.

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