Transmission RPO codes: Difference between revisions
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{| class="wikitable" | {| class="wikitable" | ||
! | ! Transmission code | ||
! Transmission | ! Transmission | ||
! Commonly listed final drive | ! Commonly listed final drive | ||
|- | |||
| MY8 | |||
| Muncie 4-speed | |||
| 3.32 | |||
|- | |||
| M19 | |||
| Muncie 4-speed | |||
| 4.10 | |||
|- | |||
| M17 | |||
| Muncie 4-speed | |||
| 3.65 | |||
|- | |||
| MT2 | |||
| Isuzu 5-speed | |||
| 3.35 | |||
|- | |||
| MG2 | |||
| Muncie/Getrag 5-speed | |||
| 3.61 | |||
|} | |||
Some separate codes are also used in Fiero references to identify final-drive ratios or final-drive-related equipment. | |||
{| class="wikitable sortable" | |||
! Code | |||
! Ratio | |||
! Category | |||
! Notes | |||
|- | |- | ||
| F17 | | F17 | ||
| 2.84 | | 2.84 | ||
| Transmission / final drive | | Transmission / final drive | ||
| Listed in enthusiast/forum references; verify application | | Listed in enthusiast/forum references; verify application | ||
|- | |- | ||
| F75 | | F75 | ||
| 3.18 | | 3.18 | ||
| Transmission / final drive | | Transmission / final drive | ||
| Listed in enthusiast/forum references; verify application | | Listed in enthusiast/forum references; verify application | ||
|- | |- | ||
| FW2 | | FW2 | ||
| 3.06 | | 3.06 | ||
| Transmission / final drive | | Transmission / final drive | ||
| Listed in forum reference as 1985-1986 V6 automatic application | | Listed in forum reference as 1985-1986 V6 automatic application | ||
|- | |||
| FW5 | |||
| 4.10 | |||
| Transmission / final drive | |||
| Commonly associated with the 1984 M19 four-speed application | |||
|- | |- | ||
| FX4 | | FX4 | ||
| 3.35 | | 3.35 | ||
| Transmission / final drive | | Transmission / final drive | ||
| Listed in enthusiast/forum references; verify application | | Listed in enthusiast/forum references; verify application | ||
|- | |- | ||
| | | FX8 | ||
| Muncie | | 3.61 | ||
| Transmission / final drive | |||
| Commonly associated with the MG2 Muncie/Getrag five-speed application | |||
|- | |- | ||
| | | GX3 | ||
| | | 3.33 | ||
| | | Transmission / final drive | ||
| Commonly listed as an automatic final-drive ratio | |||
|- | |- | ||
| | | GY5 | ||
| 3.65 | | 3.65 | ||
| | | Transmission / final drive | ||
| Commonly associated with the M17 four-speed application | |||
| | |||
|} | |} | ||
Latest revision as of 13:00, 22 July 2026
Transmission RPO codes are RPO codes used to identify factory transmission equipment on the Pontiac Fiero.
For a complete searchable list of Fiero RPO and option codes, see:
Overview
The Pontiac Fiero was available with several factory manual and automatic transaxles.
Transmission RPO codes help identify which transmission a car was originally equipped with from the factory. These codes may appear on the Service parts identification label along with engine, paint, trim, wheel, audio, and other factory build codes.
The RPO code identifies original factory equipment. It does not necessarily prove what transmission is currently installed, because many Fieros have been repaired, rebuilt, transmission-swapped, engine-swapped, or modified.
Related topics:
- Transmission
- Transmission identification
- Transmission gear ratios
- Service parts identification label
Factory transmission RPO codes
| Code | Transmission | Type | Common Fiero usage | Notes |
|---|---|---|---|---|
| MD9 | 125C / TH125C automatic transaxle | 3-speed automatic | Automatic-equipped Fieros | Factory automatic transaxle used throughout Fiero production |
| MY8 | Muncie 4-speed | 4-speed manual | Economy-oriented 1984 four-cylinder application | 3.32 final-drive ratio |
| M19 | Muncie 4-speed | 4-speed manual | 1984 four-cylinder performance application | 4.10 final-drive ratio |
| M17 | Muncie 4-speed | 4-speed manual | V6 four-speed application | 3.65 final-drive ratio |
| MT2 | Isuzu 5-speed | 5-speed manual | Four-cylinder five-speed application | 3.35 final-drive ratio |
| MG2 | Muncie/Getrag 5-speed | 5-speed manual | V6 five-speed application | 3.61 final-drive ratio |
MD9
MD9 identifies the 125C / TH125C three-speed automatic transaxle used in automatic-equipped Fieros.
The TH125 automatic was available with both the 2.5L four-cylinder and 2.8L V6 engines.
Related topics:
MY8
MY8 identifies a Muncie four-speed manual transaxle used in 1984 four-cylinder Fieros.
It is commonly associated with the 3.32 final-drive ratio and is often discussed as the economy-oriented 1984 four-speed.
Related topics:
M19
M19 identifies a Muncie four-speed manual transaxle used in 1984 four-cylinder Fieros.
It is commonly associated with the 4.10 final-drive ratio and is often discussed as the shorter-geared 1984 four-speed.
Related topics:
M17
M17 identifies the Muncie four-speed manual transaxle used with V6 Fieros before the later V6 five-speed became available.
It is commonly associated with the 3.65 final-drive ratio.
Related topics:
MT2
MT2 identifies the Isuzu five-speed manual transaxle used with four-cylinder Fieros.
In Fiero owner usage, this transmission is commonly called the Isuzu 5-speed.
Related topics:
MG2
MG2 identifies the five-speed manual transaxle used with V6 Fieros.
In Fiero owner usage, this transmission is commonly called the Getrag 5-speed. Factory service information may identify the same transmission as the Muncie 282 five-speed manual transaxle.
Related topics:
Final-drive relationship
Some Fiero transmission RPO codes are closely associated with final-drive ratios.
| Transmission code | Transmission | Commonly listed final drive |
|---|---|---|
| MY8 | Muncie 4-speed | 3.32 |
| M19 | Muncie 4-speed | 4.10 |
| M17 | Muncie 4-speed | 3.65 |
| MT2 | Isuzu 5-speed | 3.35 |
| MG2 | Muncie/Getrag 5-speed | 3.61 |
Some separate codes are also used in Fiero references to identify final-drive ratios or final-drive-related equipment.
| Code | Ratio | Category | Notes |
|---|---|---|---|
| F17 | 2.84 | Transmission / final drive | Listed in enthusiast/forum references; verify application |
| F75 | 3.18 | Transmission / final drive | Listed in enthusiast/forum references; verify application |
| FW2 | 3.06 | Transmission / final drive | Listed in forum reference as 1985-1986 V6 automatic application |
| FW5 | 4.10 | Transmission / final drive | Commonly associated with the 1984 M19 four-speed application |
| FX4 | 3.35 | Transmission / final drive | Listed in enthusiast/forum references; verify application |
| FX8 | 3.61 | Transmission / final drive | Commonly associated with the MG2 Muncie/Getrag five-speed application |
| GX3 | 3.33 | Transmission / final drive | Commonly listed as an automatic final-drive ratio |
| GY5 | 3.65 | Transmission / final drive | Commonly associated with the M17 four-speed application |
For the automatic transmission, final-drive ratio can vary by year and transmission code. See:
RPO code versus installed transmission
The transmission RPO code identifies the transmission originally assigned to the car when it was built.
It does not prove that the same transmission is still installed.
Many Fieros have had transmission replacements, clutch repairs, engine swaps, manual-to-automatic conversions, automatic-to-manual conversions, or drivetrain swaps.
When ordering parts or diagnosing a transmission, use the RPO code together with physical inspection of the actual installed transmission.
Transmission identification
Transmission identification should include:
- Service parts identification label RPO code
- Transmission case features
- Shift-cable arrangement
- Clutch or automatic-shifter hardware
- Dipstick or fill/check arrangement
- Axle and mount arrangement
- Transmission tag, stamping, or code, where present
- Model year and engine combination
- Previous repair or swap history
Because Fiero transmissions are interchangeable in some situations, physical identification is important.
Related topic:
Relationship to engine RPO codes
Transmission RPO codes are often interpreted together with engine RPO codes.
The main Fiero engine RPO codes are:
| Code | Engine | Common name |
|---|---|---|
| LR8 | 2.5L four-cylinder | Iron Duke |
| L44 | 2.8L V6 | 2.8L V6 |
A car's original engine and transmission combination can be checked using the Service Parts Identification label, but the current installed drivetrain should still be inspected directly.
Related topic:
Common mistakes
Common mistakes when using transmission RPO codes include:
- Assuming the RPO label proves the current transmission is original
- Confusing Isuzu 5-speed and Getrag 5-speed units
- Assuming all five-speed Fieros used the same transmission
- Assuming every V6 car has a Getrag 5-speed
- Assuming every four-cylinder five-speed is suitable for a V6 application
- Confusing transmission RPO codes with gear-ratio codes or transmission case codes
- Ordering parts based only on model year instead of identifying the installed transmission
Service notes
When using transmission RPO codes:
- Check the Service parts identification label first.
- Verify the installed transmission physically before ordering parts.
- Check year, engine, transmission type, and RPO code together.
- Use Transmission identification when the car has unknown history.
- Use Transmission gear ratios when exact gearing matters.
- Be cautious with swapped or rebuilt cars.
- Do not assume the current transmission matches the original RPO label.
Notes
Transmission RPO codes are factory build references. They are useful for identifying how a Fiero was originally equipped, but they are not a complete history of the car.
For modified, repaired, or swapped cars, direct inspection of the installed transmission is more important than the original RPO code alone.