Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1977FORWARD CONTROL 7.4L ENG VIN Y, AUTOMATIC TRANS, TRANS MFR CD 400/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETUNE-UPTUNE-UP PROCEDURES - V8ENGINE IDENTIFICATIONENGINE IDENTIFICATION CODE
1977 Chevrolet Forward Control 7.4L Eng VIN Y, Automatic Trans, Trans Mfr CD 400/M40
Engine Identification Code
1977 Chevrolet Forward Control 7.4L Eng VIN Y, Automatic Trans, Trans Mfr CD 400/M40SECTION Engine Identification Code
Engine code letters are suffix of Engine Identification Number. Number is stamped on pad on front of engine, below right hand cylinder head. On 454" engine, pad is located at top, front of cylinder block, below intake manifold.
1975 ENGINE CODES
| Application | Codes | ||||
|---|---|---|---|---|---|
| 350" | |||||
| Federal | |||||
| Man. Trans. | TJH, TJJ, TXD, TXK, TXX, TXR, TZF, TYT, TYA, TXK, TYC, TXD, TYX, TZC, (1) TKE, (1) TMF, (1) TJN, (1) TKN | ||||
| Auto. Trans. | TWF, TWH, TXS, TXT, TXU, TKG, TYU, TXL, TKF, TZA, TYZ, TXB, (1) TZH, (1) TZB, (1) TJE, (1) TZD, (1) TJG | ||||
| California | |||||
| Man. Trans. | TWJ, TWK, TXS, TXY, TXM, TYS, TYJ, TXJ, TXC, TYD, TYW, (1) TZL, (1) TZJ | ||||
| Auto. Trans. | TJK, TJL, TXS, TXW, TMG, TYR, TXH, TME, TYY, TXA, (1) TZM, (1) TZK | ||||
| 400" | |||||
| Federal | TLM, TLS, TLH, TLU | ||||
| California | TLL, TLR, TLD, TLT | ||||
| 454" | |||||
| Federal | |||||
| Man. Trans. | TSH, TSC | ||||
| Auto. Trans. | TSH, TSM, TSJ, TSD, TRY, TSK | ||||
| California | |||||
| Man. Trans. | TSB, TRZ | ||||
| Auto. Trans. | TSA, TSB, TSL | ||||
| 455" | |||||
| Federal | RA, RC | ||||
| California | RB | ||||
|
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1976 ENGINE CODES
| Application | Codes | ||
|---|---|---|---|
| 350" | |||
| Federal | |||
| Man. Trans. | TYC, TKA, TKH, TYX, TXD TKC, TYA, TYT, TXK | ||
| Auto. Trans. | TKF, TKB, TYZ, TXB, TKG, TYU, TKO, TXL | ||
| California | |||
| Man. Trans. | TJW, TYW, TXC, TWK, TYS, TXJ | ||
| Auto. Trans. | TJK, TYY, TXA, TJL, TYR, TXH | ||
| 400" | |||
| Federal | TLS, TLM, TLU, TLH | ||
| California | TLR, TLL, TLT, TLD | ||
| 454" | |||
| Federal | TSC, TSD, TSK, TSM, TSH | ||
| California | TRZ, TSA, TSL, TSB, TSR | ||
| 455" | |||
| Federal | RA, RC | ||
| California | RB | ||
1977 ENGINE CODES
| Application | Codes | ||||
|---|---|---|---|---|---|
| 305" | |||||
| Federal | |||||
| Man. Trans. | UTF | ||||
| Auto. Trans. | UTH | ||||
| California | |||||
| Man. Trans. | UTA | ||||
| Auto. Trans. | UTB | ||||
| 350" | |||||
| Federal | |||||
| Man. Trans. | TKC, TWD, TWF, TXD, TXK TXR, TXX, TYT, TYX | ||||
| Auto. Trans. | TKB, TKD, TWT, TXB, TXL TXT, TXU, TYU, TYZ | ||||
| California | |||||
| Man. Trans. | TWF, TWJ, TWK, TXC, TXJ, TXM, TXY, TYS, TYW | ||||
| Auto. Trans. | TJK, TJL, TWV, TXA, TXH TXS, TXW, TYR, TYY | ||||
| High Altitude | TJR, TJS | ||||
| 400" | |||||
| Federal | TLH, TLM, TLS, TLU | ||||
| California | TLD, TLL, TLR, TLT | ||||
| 403" & 455" | (1) | ||||
| 454" | |||||
| Federal | |||||
| Man. Trans. | TSC, TSK, TSM | ||||
| Auto. Trans. | TRA, TRC, TSK, TSM, TSD | ||||
| California | |||||
| Man. Trans. | TRZ, TSL, TSM | ||||
| Auto. Trans. | TRB, TRD, TSA, TSB, TSC, TSM, TSR | ||||
|
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1978 ENGINE CODES
| Application | Codes | ||
|---|---|---|---|
| 305" | |||
| Man. Trans. | UTR, UTT, UTW | ||
| Auto. Trans. | UTS, UTU, UTX | ||
| 350" | |||
| Federal | |||
| Man. Trans. | TJY, TJX, TKF, TKL, TKM, TKT, TKZ, TWY, TYA | ||
| Auto. Trans. | TKA, TKH, TKK, TKR, TKW, TKX, TWW, TWZ, TYC | ||
| California | |||
| Man. Trans. | TKS, TYB, TYH, TYJ, TYL, TXZ, TZA, TZD, TZF, TZK, TZT, TZU | ||
| Auto. Trans. | TKU, TKY, TWX, TYD, TYK, TYM, TZB, TZH, TZL, TZR, TZS, TZW | ||
| High Altitude | TYF, TZC | ||
| 400" | TLA, TLB, TLC, TLF, TLJ, TLK, TLW, TLY, TLX, TLZ | ||
| 454" | |||
| Federal | |||
| Man. Trans. | TSF | ||
| Auto. Trans. | TRH, TRK, TSF, TST, TSU | ||
| California | |||
| Man. Trans. | TRY | ||
| Auto. Trans. | TRF, TRJ, TRL, TRM, TSB, TSS | ||
1979 ENGINE CODES
| Application | Codes | ||
|---|---|---|---|
| 305" (VIN U) | |||
| Federal | |||
| Man. Trans. | TYR, UTA, UTC, UYR | ||
| Auto. Trans. | TYS, UTB, UTD, UYS | ||
| 350" (VIN L) | |||
| Federal | |||
| Man. Trans. | TBA, TBB, TBD, TBH, TBJ, TBL, TFS, TFU, TFX, TFY, TKB, TMF | ||
| Auto. Trans. | TBC, TBF, TBK, TBM, TBR, TFT, TFW, TFZ, TJA, TJB, TJS, TJT, TKC, TMH | ||
| California | |||
| Man. Trans. | TBR, TBS, TBU, TBW, TBZ, TFK, TFL, TFS, TFU, TFX, TFY | ||
| Auto. Trans. | TBR, TBS, TBT, TBX, TBY, TFJ, TFM, TFR, TFT, TFW, TFZ, TJA, TJB | ||
| High Altitude | |||
| Man. Trans. | TFS, TFU, TFX, TFY, TRZ | ||
| Auto. Trans. | TFT, TFW, TFZ, TJA, TJB, TMC, TMD, TRR, TRS | ||
| 400" (VIN R) | |||
| Federal | TLD, TLH, TLL, TLM, TLU, TTJ, TTR | ||
| California | TLR, TLS, TLT, TLU, TTJ, TTM | ||
| 454" (VIN S) | |||
| Man. Trans. | TRT, TRZ | ||
| Auto. Trans. | TRR, TRS, TRU, TRW, TRX | ||
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.