<SUBMISSION>
<ACCESSION-NUMBER>0001104659-05-002213
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20041118
<FILING-DATE>20050121
<DATE-OF-FILING-DATE-CHANGE>20050121
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>RUSH W MARVIN
<CIK>0001036504
<STATE-OF-INCORPORATION>TX
<FISCAL-YEAR-END>1231
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-20797
<FILM-NUMBER>05541295
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>2106614511
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>RUSH ENTERPRISES INC
<STREET2>PO BOX 34630
<CITY>SAN ANTONIO
<STATE>TX
<ZIP>78219
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>RUSH ENTERPRISES INC \TX\
<CIK>0001012019
<ASSIGNED-SIC>5500
<IRS-NUMBER>741733016
<STATE-OF-INCORPORATION>TX
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>555 IH 35 SOUTH
<CITY>NEW BRAUNFELS
<STATE>TX
<ZIP>78130
<PHONE>8306265200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>555 IH 35 SOUTH
<CITY>NEW BRAUNFELS
<STATE>TX
<ZIP>78130
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-11-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001012019</issuerCik>
        <issuerName>RUSH ENTERPRISES INC \TX\</issuerName>
        <issuerTradingSymbol>RUSHA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001036504</rptOwnerCik>
            <rptOwnerName>RUSH W MARVIN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>RUSH ENTERPRISES INC</rptOwnerStreet1>
            <rptOwnerStreet2>PO BOX 34630</rptOwnerStreet2>
            <rptOwnerCity>SAN ANTONIO</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78219</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman &amp; CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-11-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>750000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.25</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-11-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.25</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1833</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>3MR PARTNERS, L.P.</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The shares of Class A Common Stock were sold in an underwritten public offering that commenced on November 18, 2004.</footnote>
        <footnote id="F2">The sales price of $13.25 does not reflect underwriting commission and discounts of $0.6625 per share.</footnote>
        <footnote id="F3">Shares are held by 3MR Partners, L.P. (the &quot;Partnership&quot;), a limited partnership of which the reporting person is the general partner and one of the limited partners.  The reporting person disclaims beneficial ownership in the shares held by the Partnership except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Steven L. Keller, by power of attorney</signatureName>
        <signatureDate>2005-01-21</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
