Introduction
Over the years, we’ve seen various Bronco II buildups. Here’s an overview of the most common upgrades.
Manual Locking Hubs
The automatic hubs become unreliable with age and can fail. When they do, there’s no automatic hubs available to replace them. One of the first upgrades people do is to replace the automatic hubs with manual locking hubs.
See: Automatic To Manual Hub Conversion
Duraspark Conversion
The 2.8L is equipped with a TFI (Thick Film Ignition) ignition that is known to be problematic and fail. A common upgrade is to replace the TFI ignition with an earlier Duraspark conversion.
See: 2.8L Duraspark Conversion
Suspension Lift
A common upgrade is to add a suspension lift to make room for larger tires.
- 1.5-Inch Lift & Fender Trimming = 31-Inch Tires
- 4-Inch Lift = 31-Inch Tires
- 4-Inch Lift and Cutout Fenders / Fender Flares = 33-Inch Tires
- 6-Inch Lift = 33-Inch Tires
See: 1983–1997 Ford Ranger TTB Suspension Modification Guide
Dana 35 TTB Axle Swap
The Ford Bronco II was equipped with the Dana 28 TTB front axle. In November 1989, Ford began installing the Dana 35 TTB in its place. The Dana 28 TTB doesn’t have any aftermarket gear and locker options and is only good for tires under 33-inches. Those building a Bronco II for off-road replace the Dana 28 TTB with the stronger Dana 35 TTB.
See: Dana 28 / 35 TTB Axles (1983-1997)
See: Dana 28 TTB to Dana 35 TTB Swap
A4LD Automatic Transmission
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. One of the A4LD’s biggest enemy and cause for failure is heat. A common upgrade is to install an auxiliary transmission cooler in the transmission cooler return line.
See: Ford Ranger A4LD Automatic Transmission
Ford 8.8-Inch Rear Axle
The Bronco II came with a Ford 7.5-Inch rear axle. Even the ones built with Dana 35s. The Ford 7.5-Inch axle can handle a 33-inch tire, but for serious off-roading many off-roaders replace the 7.5-Inch axle with a Ford 8.8-Inch axle out of a Ford Explorer. Not only does it offer a larger gear size, but it also comes with a larger 31-spline axle shaft and disc brakes.
See: Ranger / Explorer 8.8-Inch Axle History & Specs
See: Explorer 8.8-Inch Axle Swap
Ford 8.8-Inch Rear Axle With Discs (Shown Upside Down)
Related Articles
Ford Bronco II Lift and Tire Size Guide
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.