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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0000075362-11-000020.txt : 20110118
<SEC-HEADER>0000075362-11-000020.hdr.sgml : 20110117
<ACCEPTANCE-DATETIME>20110118113524
ACCESSION NUMBER:		0000075362-11-000020
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20110113
FILED AS OF DATE:		20110118
DATE AS OF CHANGE:		20110118

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PLIMPTON THOMAS E
		CENTRAL INDEX KEY:			0001191931

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14817
		FILM NUMBER:		11532320

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
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
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<DESCRIPTION>PRIMARY DOCUMENT
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    <periodOfReport>2011-01-13</periodOfReport>

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

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            <rptOwnerName>PLIMPTON THOMAS E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>777 106TH AVENUE NE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BELLEVUE</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98004</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice Chairman</officerTitle>
        </reportingOwnerRelationship>
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                <transactionPricePerShare>
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                <footnoteId id="F5"/>
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            <exerciseDate>
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            <expirationDate>
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            <expirationDate>
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            <underlyingSecurity>
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                <underlyingSecurityShares>
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        <derivativeHolding>
            <securityTitle>
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                <footnoteId id="F5"/>
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            <exerciseDate>
                <value>2009-01-01</value>
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            <expirationDate>
                <value>2016-01-26</value>
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            <underlyingSecurity>
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        <derivativeHolding>
            <securityTitle>
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            <conversionOrExercisePrice>
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            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2010-01-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2017-01-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
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                <underlyingSecurityShares>
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                <footnoteId id="F5"/>
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                <value>45.74</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2011-01-01</value>
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            <expirationDate>
                <value>2018-01-30</value>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
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                <underlyingSecurityShares>
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            <ownershipNature>
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                    <value>D</value>
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        <derivativeHolding>
            <securityTitle>
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                <footnoteId id="F5"/>
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            <conversionOrExercisePrice>
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            <exerciseDate>
                <value>2012-01-01</value>
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            <expirationDate>
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            </expirationDate>
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                <value>2020-02-02</value>
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                <underlyingSecurityShares>
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                <value>COMMON STOCK (LTIP)</value>
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                <footnoteId id="F6"/>
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                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
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                <underlyingSecurityShares>
                    <value>7690.42</value>
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                <sharesOwnedFollowingTransaction>
                    <value>7690.42</value>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>COMMON STOCK (DICP)</value>
                <footnoteId id="F7"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F7"/>
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            <exerciseDate>
                <footnoteId id="F7"/>
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                <footnoteId id="F7"/>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4317.22</value>
                </underlyingSecurityShares>
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                <sharesOwnedFollowingTransaction>
                    <value>4317.22</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>D</value>
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                    <value></value>
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        </derivativeHolding>
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    <footnotes>
        <footnote id="F1">Shares held in PACCAR Savings Investment Plan (SIP).</footnote>
        <footnote id="F2">December 6, 2010 dividend on PACCAR Savings Investment Plan (SIP) shares reinvested pursuant to SIP.  (SIP information based on most recent report from SIP trustee - received January 13, 2011).</footnote>
        <footnote id="F3">December 29, 2010 dividend on PACCAR Savings Investment Plan (SIP) shares reinvested pursuant to SIP.  (SIP information based on most recent report from SIP Trustee - received January 13, 2011.)</footnote>
        <footnote id="F4">Shares awarded January 12, 2011 under SIP.  (SIP information based on most recent report from SIP trustee - received January 13, 2011).</footnote>
        <footnote id="F5">Option to buy awarded under PACCAR Long Term Incentive Plan (LTIP).</footnote>
        <footnote id="F6">Share units held in deferred phantom stock account under LTIP convertible to common stock on a one-for-one basis upon satisfaction of all applicable vesting conditions.</footnote>
        <footnote id="F7">Share units held in deferred phantom stock account under PACCAR Deferred Incentive Compensation Plan (DICP) convertible to common stock on a one-for-one basis upon satisfaction of all applicable vesting conditions.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Thomas E. Plimpton by David C. Anderson POA</signatureName>
        <signatureDate>2011-01-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----