<?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>0001196974</rptOwnerCik>
            <rptOwnerName>WEHMEIER HELGE H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BAYER CORP</rptOwnerStreet1>
            <rptOwnerStreet2>HILLSIDE DRIVE BLACKBURN RD</rptOwnerStreet2>
            <rptOwnerCity>SEWICKLEY</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>15143</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>110</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>28.48</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>19033</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 beneficially owned as of December 31, 2003.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>/s/  HELGE WEHMEIER</signatureName>
        <signatureDate>2003-01-05</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2004-01-02
0
0000097216
TEREX CORP
TEX
0001196974
WEHMEIER HELGE H
BAYER CORP
HILLSIDE DRIVE BLACKBURN RD
SEWICKLEY
PA
15143
1
0
0
0
Common Stock, par value $.01
2004-01-02
4
P
0
110
28.48
A
19033
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 beneficially owned as of December 31, 2003.
/s/  HELGE WEHMEIER
2003-01-05