S-8

Registration No. 333-               

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

PACCAR Inc

(Exact name of registrant as specified in its charter)

Delaware	91-0351110
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

777–106th Avenue N.E. Bellevue, Washington	98004
(Address of Principal Executive Offices)	(Zip Code)

PACCAR Inc Savings Investment Plan

(Full title of the plan)

Kevin J. Fay
PACCAR Inc
777 106th Ave. N.E.
Bellevue, WA  98004

(Name and address of agent for service)

(425) 468-7607

(Telephone Number, including area code, of agent for service)

CALCULATION OF REGISTRATION FEE

Title of securities to be registered(1)	Amount to be registered(2)	Proposed maximum  offering price per share	Proposed maximum  aggregate offering price(3)		Amount of registration fee(4)
Common Stock, $1 par value(5)	12,000,000 shares	Not applicable	$	787,980,000	$	84,313.86

(1)Pursuant to Rule 416(c) under the Securities Act of 1933, as amended (the “Securities Act”), this registration statement also covers an indeterminate amount of interests to be offered or sold pursuant to the employee benefit plan described herein.

(2)Includes an indeterminate number of additional shares that may be issued to adjust the number of shares issued pursuant to the employee benefit plans described herein as the result of any future stock split, stock dividend or similar adjustment of the Registrant’s outstanding common stock.

(3)Estimated solely for the purpose of calculating the registration fee.

(4)Estimated pursuant to Rules 457(c) and 457(h) under the Securities Act solely for purposes of calculating amount of registration fee, based upon the average of the high and low prices reported on December 18, 2006, as reported on The NASDAQ Stock Market.

(5)Includes preferred stock purchase rights.

REGISTRATION OF ADDITIONAL SECURITIES

This Registration Statement relates to the registration of additional securities under the PACCAR Inc Savings Investment Plan.  In accordance with General Instruction E of Form S-8 under the Securities Act, the contents of the previous Registration Statement on Form S-8 related to the Savings Investment Plan (Registration No. 333—52230, filed with the Securities and Exchange Commission on December 20, 2000) are incorporated herein by reference and made part of this Registration Statement, except as amended hereby.

The following documents are filed as exhibits to this Registration Statement:

4.1PACCAR Inc Savings Investment Plan (incorporated by reference to Exhibit 10(i) to the Quarterly Report on Form 10-Q for the period ended September 30, 2005).

4.2Rights agreement dated as of December 10, 1998 between PACCAR Inc and First Chicago Trust Company of New York setting forth the terms of the Series A Junior Participating Preferred Stock, no par value per share (incorporated by reference to Exhibit 4.1 of the Current Report on Form 8-K dated December 21, 1998).

4.3Amendment Number 1 to rights agreement dated as of December 10, 1998 between PACCAR Inc and First Chicago Trust Company of New York appointing Wells Fargo Bank N.A. as successor rights agent, effective as of the close of business September 15, 2000 (incorporated by reference to Exhibit (4)(b) of the Quarterly Report on Form 10-Q for the period ended September 30, 2000).

23Consent of Ernst & Young LLP, Independent Registered Public Accounting Firm.

24Power of Attorney.

In lieu of an Internal Revenue Service (“IRS”) determination letter that the Plan is qualified under Section 401 of the Internal Revenue Code, the undersigned Registrant hereby undertakes that it will submit the Plan and the amendments thereto to the IRS in a timely manner and will make all changes required by the IRS to qualify the Plan.

SIGNATURES

The Registrant.

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 in relation to the PACCAR Inc Savings Investment Plan and has duly caused this registration statement on Form S-8 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Bellevue, State of Washington, on this 19th day of December, 2006.

PACCAR Inc
By:	/s/ J. M. D’Amato
	J. M. D’Amato
	Secretary

2

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities indicated on December 19, 2006.

Signature	Title
/s/ M. C. Pigott	Chairman and Chief Executive Officer (principal executive officer)
M. C. Pigott	Director, PACCAR Inc
	Vice Chairman
/s/ M. A. Tembreull	(principal financial officer)
M. A. Tembreull	Director, PACCAR Inc
/s/ R. E. Armstrong	Vice President and Controller
R. E. Armstrong	(principal accounting officer)
*	Director, PACCAR Inc
A. J. Carnwath
*	Director, PACCAR Inc
J. M. Fluke, Jr.
*	Director, PACCAR Inc
S. F. Page
*	Director, PACCAR Inc
R. T. Parry
*	Director, PACCAR Inc
J. C. Pigott
*	Director, PACCAR Inc
W. G. Reed, Jr.
*	Director, PACCAR Inc
H. A. Wagner
*	Director, PACCAR Inc
C. R. Williamson

*By:	/s/ M. C. Pigott
	M. C. Pigott Attorney-in-fact

3

The Plan.

Pursuant to the requirements of the Securities Act of 1933, the trustees (or other persons who administer the employee benefit plan) have duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Bellevue, State of Washington, on December 19, 2006.

PACCAR INC SAVINGS INVESTMENT PLAN
By:	/s/ M. C. Pigott
	M. C. Pigott
	Chairman and Chief Executive Officer
	PACCAR Inc

INDEX TO EXHIBITS

Exhibit Number	Description
4.1	PACCAR Inc Savings Investment Plan (incorporated by reference to the Quarterly Report on Form 10-Q for the period ended September 30, 2005).
4.2	Rights agreement dated as of December 10, 1998 between PACCAR Inc and First Chicago Trust Company of New York setting forth the terms of the Series A Junior Participating Preferred Stock, no par value per share (incorporated by reference to Exhibit 4.1 of the Current Report on Form 8-K dated December 21, 1998).
4.3	Amendment Number 1 to rights agreement dated as of December 10, 1998 between PACCAR Inc and First Chicago Trust Company of New York appointing Wells Fargo Bank N.A. as successor rights agent, effective as of the close of business September 15, 2000 (incorporated by reference to Exhibit (4)(b) of the Quarterly Report on Form 10-Q for the quarter ended September 30, 2000).
23	Consent of Ernst & Young LLP, Independent Registered Public Accounting Firm.
24	Power of Attorney.

4

EX-23

Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement on Form S-8 our reports dated February 17, 2006, with respect to the consolidated financial statements of PACCAR Inc incorporated by reference in its Annual Report (Form 10-K) for the year ended December 31, 2005, and PACCAR Inc management’s assessment of the effectiveness of internal control over financial reporting, and the effectiveness of internal control over financial reporting of PACCAR Inc, filed with the Securities and Exchange Commission.

	/s/ Ernst & Young LLP
Seattle, Washington
December 18, 2006

EX-24

Exhibit 24

POWER OF ATTORNEY

We, the undersigned directors of PACCAR Inc, a Delaware corporation (the “Company”), hereby severally constitute and appoint Mark C. Pigott our true and lawful attorney-in-fact, with full power do any and all acts and execute any and all instruments which said attorney may deem appropriate to effect a registration statement on Form S-8 in connection with the PACCAR Inc Savings Investment Plan to be filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended. Said power includes signing for us, and in our names in our capacity as director the registration statement on Form S-8 together with any and all amendments to said registration statement, and hereby ratify and confirm our signatures as they may be signed by our attorney-in-fact to the registration statement.

IN WITNESS WHEREOF, each of the undersigned has executed this power of attorney as of July 11, 2006.

/s/ Alison J. Carnwath	/s/ William G. Reed, Jr.
Alison J. Carnwath	William G. Reed, Jr.
Director, PACCAR Inc	Director, PACCAR Inc
/s/ John M. Fluke, Jr.	/s/ Michael A. Tembreull
John M. Fluke, Jr.	Michael A. Tembreull
Director, PACCAR Inc	Director, PACCAR Inc
/s/ Stephen F. Page	/s/ Harold A. Wagner
Stephen F. Page	Harold A. Wagner
Director, PACCAR Inc	Director, PACCAR Inc
/s/ Robert T. Parry	/s/ Charles R. Williamson
Robert T. Parry	Charles R. Williamson
Director, PACCAR Inc	Director, PACCAR Inc
/s/ James C. Pigott
James C. Pigott
Director, PACCAR Inc