<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-01-02</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000097216</issuerCik>
        <issuerName>TEREX CORP</issuerName>
        <issuerTradingSymbol>TEX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001140113</rptOwnerCik>
            <rptOwnerName>SACHS DAVID A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O TEREX CORP</rptOwnerStreet1>
            <rptOwnerStreet2>500 POST ROAD EAST, SUITE 320</rptOwnerStreet2>
            <rptOwnerCity>WESTPORT</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06880</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.01</value>
            </securityTitle>
            <transactionDate>
                <value>2004-01-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>154</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>28.48</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>118806</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares represent payment of meetings fees which were purchased through the Company's deferred compensation plan.</footnote>
        <footnote id="F2">Price is as of December 31, 2003, the date the director was entitled to receive his meeting fee retainer.</footnote>
        <footnote id="F3">Represent shares benefecially owned as of December 31, 2003.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>/s/  DAVID A. SACHS</signatureName>
        <signatureDate>2004-01-05</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2004-01-02
0
0000097216
TEREX CORP
TEX
0001140113
SACHS DAVID A
C/O TEREX CORP
500 POST ROAD EAST, SUITE 320
WESTPORT
CT
06880
1
0
0
0
Common Stock, par value $.01
2004-01-02
4
P
0
154
28.48
A
118806
D
Shares represent payment of meetings fees which were purchased through the Company's deferred compensation plan.
Price is as of December 31, 2003, the date the director was entitled to receive his meeting fee retainer.
Represent shares benefecially owned as of December 31, 2003.
/s/  DAVID A. SACHS
2004-01-05