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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-03-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000099106</issuerCik>
        <issuerName>TRANS LUX CORP</issuerName>
        <issuerTradingSymbol>TLX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001192075</rptOwnerCik>
            <rptOwnerName>LISS VICTOR S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TRAN-LUX CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>110 RICHARDS AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NORWALK</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06854</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>7 1/2% Conv. Sub. Notes due 2006</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>14.013</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-03-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>20000</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-07-09</value>
            </exerciseDate>
            <expirationDate>
                <value>2006-12-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1427</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>0</value>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>8 1/4% Limited Conv. Sr. Sub. Notes due 2012</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>9</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-03-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>20000</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-03-13</value>
            </exerciseDate>
            <expirationDate>
                <value>2007-03-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2222</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>30000</value>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person disposed of $20,000 of 7 1/2% Convertible Subordinated Notes due 2006 for $20,000 8 1/4% Limited Convertible Senior Subordinates Notes due 2012 in an Issuer Exchange Offer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Victor Liss</signatureName>
        <signatureDate>2006-03-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2006-03-13
0
0000099106
TRANS LUX CORP
TLX
0001192075
LISS VICTOR S
TRAN-LUX CORPORATION
110 RICHARDS AVENUE
NORWALK
CT
06854
1
0
0
0
7 1/2% Conv. Sub. Notes due 2006
14.013
2006-03-13
4
D
0
20000
0
D
2004-07-09
2006-12-01
Common Stock
1427
0
D
8 1/4% Limited Conv. Sr. Sub. Notes due 2012
9
2006-03-13
4
A
0
20000
0
A
2006-03-13
2007-03-01
Common Stock
2222
30000
D
The reporting person disposed of $20,000 of 7 1/2% Convertible Subordinated Notes due 2006 for $20,000 8 1/4% Limited Convertible Senior Subordinates Notes due 2012 in an Issuer Exchange Offer.
Victor Liss
2006-03-21