Ford Bronco II Transmissions: Specs, Codes, and Gear Ratios
This page is a complete reference guide to Ford Bronco II transmissions used from 1984 through 1990. It covers every factory-installed automatic and manual 4×4 transmission, including gear ratios, transmission codes, model years used, physical dimensions, and known strengths or weaknesses.
All Bronco II models were equipped with 4WD-style transmissions. Two-wheel-drive Bronco II models used a “dummy” transfer case, making transmission identification especially important for swaps, rebuilds, and drivetrain upgrades.
Transmissions Covered on This Page
- C5 Automatic (Code W) – Non-computer-controlled 3-speed automatic with lockup torque converter
- A4LD Automatic (Code T) – 4-speed overdrive automatic with electronic lockup
- Toyo Kogyo TK4 (Code X) – 4-speed manual transmission
- Toyo Kogyo TK5 (Code 5) – 5-speed manual transmission
- Mitsubishi FM145 & FM146 (Code D) – 5-speed manual transmissions
- Mazda M5OD-R1 (Code M) – 5-speed manual transmission
Use this guide to identify your transmission by code, year, or visual characteristics, compare gear ratios, and understand which transmissions are best suited for off-road use, daily driving, or drivetrain swaps.
|
Automatics |
Trans Code |
Year Used |
Gear Ratios |
| C5 | W | 1984 | 1st: 2.46
2nd: 1.46 3rd: 1.00 |
| A4LD | T | 1985-1990 | 1st: 2.47
2nd: 1.47 3rd: 1.00 4th: 0.75 |
|
Manuals |
Trans Code |
Year Used |
Gear Ratios |
| Toyo Koygo TK4 | X | 1984 | 1st: 3.96
2nd: 2.08 3rd: 1.39 4th: 1.00 |
| Toyo Koygo TK5 | 5 | 1984-1987 | 1st: 3.96
2nd: 2.08 3rd: 1.39 4th: 1.00 5th: 0.84 |
| Mitsubishi FM145 | D | 1985-1987 | 1st: 3.76
2nd: 2.21 3rd: 1.51 4th: 1.00 5th: 0.81 Reverse = 3.400 |
| Mitsubishi FM146 | D | 1988-1990 | 1st: 3.76
2nd: 2.21 3rd: 1.51 4th: 1.00 5th: 0.81 Reverse = 3.400 |
| Mazda M5OD | M | 1988-1990 | 1st: 3.72
2nd: 2.20 3rd: 1.50 4th: 1.00 5th: 0.79 Reverse = 3.40 |
| Mitsubishi FM132 | ? | 1988-1990 | 5-Speed (Unknown) |
All Bronco II’s Used 4×4 Transmissions
All Ford Bronco II’s are equipped with 4×4 type transmissions. The 2wd Bronco II’s use a “dummy” transfer case.
Automatic Transmissions
C5 3-Speed Automatic
The C5 is essentially a C4, but with a lock-up clutch in the torque converter to improve highway fuel economy. The C5 was used in the 1983-1985 4X4 Ford Ranger. The C5 is a good transmission, and was the only automatic used in a 4×4 Ford Ranger that wasn’t computer controlled.
(C5 Automatic Transmission – Click To Enlarge)
A4LD 4-Speed Automatic
The C3 was modified into the A4LD 4-speed automatic by adding an overdrive gear, which the C3 lacked. This was the first Ford automatic to use an EEC-controlled torque converter lock-up clutch. Electronic shift control for the 3–4 shift was later added, another first, though other gears remained hydraulic. The A4LD eventually went on to become the 4R44E and 4R55E in 1995.
The A4LD had reliability issues from 1985-1987. Reliability began to improve in mid-1988 when Ford introduced the dual solenoid setup. Models from 1989 and later benefited from Ford’s broader engineering push to improve “Noise, Vibration, and Harshness” (NVH) and general durability, making them noticeably better than 1985–1987 models.
For more information on the A4LD’s problems, repairs and improvements, check out: Ford Ranger A4LD Automatic Transmission
(A4LD Automatic Transmission – Click To Enlarge)
(A4LD Automatic Transmission – Click To Enlarge)
Manual Transmissions:
Toyo Koygo (TK-4) 4-Speed Code “X”
Offered in 1984
Overall Length of 24-Inches
Adapter length is 6.812-Inches long
Toyo Koygo (TK-5) 5-Speed Code “5”
This is a fully synchronized overdrive transmission with a fifth gear overdrive that is set apart from the Mitsubishi 5-Speed by its cast, ribbed bottom cover. The case configuration is also more rounded than the Mitsubishi. The Toyo Koygo seems to be the more common of the Ranger / Bronco II manual transmissions.
Offered from 1984-1987
Overall 4WD Length 25.937-Inches
Adapter Length 8.750-Inches
Ford P/N E57A-7003-DA
Toyo Koygo TK4 & TK5 Exploded View With Part Numbers
(Photo of TK-5 with photo of pan bottom inserted in lower left corner of photo)
Mitsubishi 5-Speed Code ‘D’
This is a fully synchronized 5-Speed manual transmission with a fifth gear overdrive. It has a stamped metal pan on the bottom much like an automatic transmission and the main case is tapered toward the rear.
Mitsubishi FM145: A 5-speed manual used from around 1985-1987.
Mitsubishi FM146: A 5-speed manual that succeeded the FM145, typically in models from 1988 onwards.
Assembled 4WD Length – 28.687-Inches
Adapter Length – 11.50-Inches
FM145 P/N E67A-7003-FA
The FM146 is 2-inches longer than the FM145
Mitsubishi FM145 & FM146 Exploded View With Part Numbers
(Photo of FM146 with photo of pan bottom inserted in upper right corner of photo.)
(Mitsubishi FM145 manual transmission)
Mazda M50D-R1 5-Speed Code “M”
This is a top shift fully synchronized transmission. This has a light duty aluminum case and has a rectangular shape casting ribs with a large top cover. The R-2 is known for leaking oil from a rubber plug in the top cover. You should replace the rubber plug with a steel Dorman cup plug P/N 555-108 or Dana P/N 219-3052. You will need 3 plugs. These transmissions often melt down due to the oil loss caused by these plugs.
Many owners have gone with synthetic transmission fluid hoping to extend the life of the transmission. Synthetic fluid handles high temperatures and pressures better than conventional fluids.
The hydraulic clutch, slave cylinder/throwout bearing is another item you should pay close attention to. After time, the slave cylinder fails to release the clutch completely. If you are having trouble shifting into 1st and reverse while stationary or if your truck creeps forward with the clutch pedal depressed the slave cylinder/throwout bearing is probably at fault. Unfortunately, there is no easy fix here as the transmission must be removed to replace the combination slave cylinder and throwout bearing.
Offered from 1988-1990
Mazda M50D-R1 Exploded View With Part Numbers
Last Updated:
About The Author
Jim Oaks is a longtime Ford truck and SUV enthusiast and the founder of The Ranger Station and Bronco II Corral. With decades of hands-on experience, he writes both technical and non-technical articles covering the Ford Bronco II, including mechanical systems, factory engineering, common upgrades, and detailed feature vehicle write-ups.
In addition to technical content, Jim documents Bronco II history, rare factory and aftermarket models, production details, and original Ford marketing materials. His work is based on firsthand experience, original documentation, and long-term involvement in the Ford enthusiast community.
Through his sites, Jim has built comprehensive reference libraries that serve owners, builders, restorers, collectors, and historians, helping preserve the Bronco II’s technical knowledge and historical significance.