<?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>0001166570</rptOwnerCik>
            <rptOwnerName>JACOBS DR DONALD P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></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>20962</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">Total share ownership as of April 8, 2004, reflecting an adjustment due to an error showing an extra 1,014 shares being purchased on Mr. Jacobs' behalf on January 2, 2003.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ DR DONALD P JACOBS</signatureName>
        <signatureDate>2004-04-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0201
4
2004-04-08
0
0000097216
TEREX CORP
TEX
0001166570
JACOBS DR DONALD P
1
0
0
0
Common Stock, par value $.01
2004-04-08
4
P
0
85
36.97
A
20962
D
Shares purchased through Company Deferred Compensation Plan representing payment of first quarter meeting fees.
Represent share price as of March 31, 2004.
Total share ownership as of April 8, 2004, reflecting an adjustment due to an error showing an extra 1,014 shares being purchased on Mr. Jacobs' behalf on January 2, 2003.
/s/ DR DONALD P JACOBS
2004-04-08