I was reading on here a short time back and found a thread ( or graph) showing the gear ratios of all the different trans that were installed into the fiero. I want to change my trans to achieve better fuel mileage. But don't want to go to the expense of the Pontiac 6 speed. Does anyone know where I can find that graph or advise me of a good trans to install for better fuel mileage. Thanks
trans gear ratios
- Thread starter jacob951
- Start date
Zimgxp
New member
Sounds like alot of work for minimal gains. If you are going from a 4 speed, then maybe.
The graph was probably for the auto transaxles. By changing gear and chain sizes you can go as low as 2.75 and as high as 3.91.
The 5-spd getrag came with a 3.61 and the 4-spd had 2.89 (only used on very limited 4-spds in 1984) 4.11 (used on 1984) and 3.65 (used with all V-6's) The 5-spd isuzu was 3.35
The 4-spd FD gears are interchangeable between the 4-cyl version and the V-6 version. The difference between them is just the trans case. The V-6 had a slightly thicker case and more webbing for strength.
This list may help:
General Information
MD9 3-SPEED AUTO 125THC ONLY AUTO USED
MG2 5-SPEED MANUAL MUNCIE 3.61 RATIO V6 ONLY
MT2 5-SPEED MANUAL ISUZU 3.35 RATIO L4 ONLY
MY8 4-SPEED MANUAL MUNCIE 3.32 RATIO 1984 L4 ONLY
M17 4-SPEED MANUAL MUNCIE 3.65 RATIO V6 ONLY
M19 4-SPEED MANUAL MUNCIE 4.10 RATIO 1984 L4 ONLY
Note: MG2 is the Getrag-designed Muncie built transaxle
Note: the V6 Muncie is stronger than the L4.
Gear ratios for manual transaxles
Final
1st 2nd 3rd 4th 5th Drive RPO
1984 L4 3.53 1.95 1.24 0.73 3.32 MY8
1984 L4 3.53 1.95 1.24 0.73 4.10 M19
1985 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1985 V6 3.31 1.95 1.24 0.81 3.65 M17
1986 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1986 V6 3.31 1.95 1.24 0.81 3.65 M17
1987 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1987 V6 3.50 2.05 1.38 0.94 0.72 3.61 MG2
1988 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1988 V6 3.50 2.05 1.38 0.94 0.72 3.61 MG2
Gear ratios for automatic transaxles
1st 2nd 3rd
MD9 2.84 1.60 1.00
Final
Drive Code RPO
1984 3.18 PF MD9
1985 3.06 CD MD9
1985 3.18 PF MD9
1986 3.06 6CD MD9
1986 3.18 6PF MD9
1987 3.33 7CPC MD9
1987 2.84 7PSC MD9
1988 3.33 8CPC MD9
1988 2.84 8PSC MD9
The 5-spd getrag came with a 3.61 and the 4-spd had 2.89 (only used on very limited 4-spds in 1984) 4.11 (used on 1984) and 3.65 (used with all V-6's) The 5-spd isuzu was 3.35
The 4-spd FD gears are interchangeable between the 4-cyl version and the V-6 version. The difference between them is just the trans case. The V-6 had a slightly thicker case and more webbing for strength.
This list may help:
General Information
MD9 3-SPEED AUTO 125THC ONLY AUTO USED
MG2 5-SPEED MANUAL MUNCIE 3.61 RATIO V6 ONLY
MT2 5-SPEED MANUAL ISUZU 3.35 RATIO L4 ONLY
MY8 4-SPEED MANUAL MUNCIE 3.32 RATIO 1984 L4 ONLY
M17 4-SPEED MANUAL MUNCIE 3.65 RATIO V6 ONLY
M19 4-SPEED MANUAL MUNCIE 4.10 RATIO 1984 L4 ONLY
Note: MG2 is the Getrag-designed Muncie built transaxle
Note: the V6 Muncie is stronger than the L4.
Gear ratios for manual transaxles
Final
1st 2nd 3rd 4th 5th Drive RPO
1984 L4 3.53 1.95 1.24 0.73 3.32 MY8
1984 L4 3.53 1.95 1.24 0.73 4.10 M19
1985 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1985 V6 3.31 1.95 1.24 0.81 3.65 M17
1986 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1986 V6 3.31 1.95 1.24 0.81 3.65 M17
1987 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1987 V6 3.50 2.05 1.38 0.94 0.72 3.61 MG2
1988 L4 3.73 2.04 1.45 1.03 0.74 3.35 MT2
1988 V6 3.50 2.05 1.38 0.94 0.72 3.61 MG2
Gear ratios for automatic transaxles
1st 2nd 3rd
MD9 2.84 1.60 1.00
Final
Drive Code RPO
1984 3.18 PF MD9
1985 3.06 CD MD9
1985 3.18 PF MD9
1986 3.06 6CD MD9
1986 3.18 6PF MD9
1987 3.33 7CPC MD9
1987 2.84 7PSC MD9
1988 3.33 8CPC MD9
1988 2.84 8PSC MD9
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