-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 TY7AzmJRm+058QFsAvFQxQ==

<SEC-DOCUMENT>0000075362-08-000006.txt : 20080103
<SEC-HEADER>0000075362-08-000006.hdr.sgml : 20080103
<ACCEPTANCE-DATETIME>20080103210425
ACCESSION NUMBER:		0000075362-08-000006
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080102
FILED AS OF DATE:		20080103
DATE AS OF CHANGE:		20080103

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PACCAR INC
		CENTRAL INDEX KEY:			0000075362
		STANDARD INDUSTRIAL CLASSIFICATION:	MOTOR VEHICLES & PASSENGER CAR BODIES [3711]
		IRS NUMBER:				910351110
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		PACCAR BUILDING
		STREET 2:		777 106TH AVENUE NE
		CITY:			BELLEVUE
		STATE:			WA
		ZIP:			98004
		BUSINESS PHONE:		425 468 7383

	MAIL ADDRESS:	
		STREET 1:		PACCAR BUILDING
		STREET 2:		777 106TH AVENUE NE
		CITY:			BELLEVUE
		STATE:			WA
		ZIP:			98004

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PACIFIC CAR & FOUNDRY CO
		DATE OF NAME CHANGE:	19720707

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Parry Robert T
		CENTRAL INDEX KEY:			0001302372

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14817
		FILM NUMBER:		08509176

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		818-225-4111

	MAIL ADDRESS:	
		STREET 1:		4500 PARK GRANADA
		CITY:			CALABASAS
		STATE:			CA
		ZIP:			91302
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-01-02</periodOfReport>

    <issuer>
        <issuerCik>0000075362</issuerCik>
        <issuerName>PACCAR INC</issuerName>
        <issuerTradingSymbol>PCAR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001302372</rptOwnerCik>
            <rptOwnerName>Parry Robert T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>777 106TH AVENUE NE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BELLEVUE</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98004</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7116</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>PHANTOM STOCK UNITS</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-01-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1699</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>52.98</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1699</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1699</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On September 11, 2007 PACCAR declared a stock dividend of one additional share of common stock for every two shares of common stock payable October 9, 2007 to all holders of record of common stock on September 25, 2007.  As a result of the stock dividend the reporting person received  2,372 additional shares of PACCAR common stock.</footnote>
        <footnote id="F2">Restricted stock units awarded under PACCAR Restricted Stock and Deferred Compensation Plan for Non-Employee Directors (RSDCP).</footnote>
        <footnote id="F3">The units are to be settled 1-for-1 in PACCAR common stock after termination of the Reporting Person's status as a non-employee director.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Robert T. Parry by Janice M. D'Amato POA</signatureName>
        <signatureDate>2008-01-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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