<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-08</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>2004-04-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>85</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.97</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>21494</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares purchased through Company Deferred Compensation Plan representing payment of first quarter meeting fees.</footnote>
        <footnote id="F2">Represent share price as of March 31, 2004.</footnote>
        <footnote id="F3">Represent shares beneficially owned as of April 8, 2004.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/  HELGE H. WEHMEIER</signatureName>
        <signatureDate>2004-04-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0201
4
2004-04-08
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
2004-04-08
4
P
0
85
36.97
A
21494
D
Shares purchased through Company Deferred Compensation Plan representing payment of first quarter meeting fees.
Represent share price as of March 31, 2004.
Represent shares beneficially owned as of April 8, 2004.
/s/  HELGE H. WEHMEIER
2004-04-08