Tell Original Trans from VIN
Thread Starter
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Tell Original Trans from VIN
I found what appears to be a good deal on an '88 4+3 for sale, and I want to verify that it was originally a 4+3 car. Is there a VIN digit that identifies the original transmission? I know 10th is model year and 8th is engine, but is there one for the trans?
Le Mans Master
Joined: Oct 2007
Posts: 9,698
Likes: 3,466
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
Time to get on track again? 
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
- 1986 Original Owner -
Joined: Apr 1999
Posts: 3,193
Likes: 139
From: North Yorkshire, England
Cruise-In I Veteran
Cruise-In II Veteran
Cruise-In III Veteran
Cruise-In IV Veteran
Cruise-In VII Veteran
You can check the engine ID pad forward of the RH cylinder head. The 88 with MT should have ZMC after the VXXXX where the Xs are the engine build date.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Thread Starter
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
If that is true when I had my 82 trans am and they ran the vin number for smoging he exclaimed hey did you know this car at one time had an automatic. The LG-4 could have had either transmission and there was never a vacuum line decal or other informative decals present.
Can anyone explain that one?
Can anyone explain that one?
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
If that is true when I had my 82 trans am and they ran the vin number for smoging he exclaimed hey did you know this car at one time had an automatic. The LG-4 could have had either transmission and there was never a vacuum line decal or other informative decals present.
Can anyone explain that one?
Can anyone explain that one?
H= 305 cu in LG4
7= 305 cu in LU5 (1982) and L69 (1983)
S= 305 cu in LU5 (1983)
G= 305 cu in L69 (1984)
The LG4 motor was a carb motor and the LU5 was a TB "Cross-Fire" motor. IIRC, the LU5 motors only got auto trannies while the LG4 got 5-speeds. I had an '83 T/A with a 5-speed and carb 305. The L69 was a "high performance" version (190HP
) that had a QuadraJet carb and only available with a 5-speed.So it would have been possible for somebody to swap in a different trans, but in the case of the Pontiac VIN, the 8th digit defined a specific engine/trans combo done only by the factory.
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
In the 82-84 Firebird there were 4 possible engines and codes (8th digit of the VIN)
H= 305 cu in LG4
7= 305 cu in LU5 (1982) and L69 (1983)
S= 305 cu in LU5 (1983)
G= 305 cu in L69 (1984)
The LG4 motor was a carb motor and the LU5 was a TB "Cross-Fire" motor. IIRC, the LU5 motors only got auto trannies while the LG4 got 5-speeds. I had an '83 T/A with a 5-speed and carb 305. The L69 was a "high performance" version (190HP ) that had a QuadraJet carb and only available with a 5-speed.
So it would have been possible for somebody to swap in a different trans, but in the case of the Pontiac VIN, the 8th digit defined a specific engine/trans combo done only by the factory.
H= 305 cu in LG4
7= 305 cu in LU5 (1982) and L69 (1983)
S= 305 cu in LU5 (1983)
G= 305 cu in L69 (1984)
The LG4 motor was a carb motor and the LU5 was a TB "Cross-Fire" motor. IIRC, the LU5 motors only got auto trannies while the LG4 got 5-speeds. I had an '83 T/A with a 5-speed and carb 305. The L69 was a "high performance" version (190HP
) that had a QuadraJet carb and only available with a 5-speed.So it would have been possible for somebody to swap in a different trans, but in the case of the Pontiac VIN, the 8th digit defined a specific engine/trans combo done only by the factory.
Le Mans Master
Joined: Dec 2006
Posts: 5,154
Likes: 2
From: Ft Myers Florida
You can send the Vin to a dealer and from that they can get a builkd sheet with all options including color/interior/exterior, cloth or leather etc etc all of which are not on the VIN either.
