Ford 8-Speed Automatic Transmission

Introduction

The 8-speed automatic transmission used in the Ford Maverick and Bronco Sport is the Ford 8F35 unit, a transverse-mounted transmission designed for front-wheel or all-wheel drive applications. It was co-developed with General Motors and is known for its compact design, efficiency, and some early model shifting and seal issues.

Design and Specifications

The Ford 8F35 transmission is part of the Ford 8F family and uses a sophisticated design to achieve its eight forward speeds.

Co-development: The 8F35 is derived from the General Motors 9T50 design, part of a joint venture between Ford and GM to share transmission designs. Ford tailored its version to its specific torque limits and declined to use the 9-speed in favor of an 8-speed unit, which it felt provided better performance and fuel economy balance.

Torque Rating: It is designed for engines producing up to approximately 350 Newton-meters (260 lb-ft) of torque. The 2.0L EcoBoost engine in the Maverick and Bronco Sport is rated at 275 lb-ft, which is slightly above the official rating but managed with robust cooling systems in towing packages.

Key Features: It features a selectable one-way clutch (SOWC), an advanced thermal management system with a fluid warmer and cooler bypass valve and uses Ford Mercon® ULV fluid. The transmission control module (PCM) manages shift points through an adaptive learning system that adjusts to driving style.

Operation: The 8F35 can skip gears under light acceleration to enhance fuel efficiency but will use more gears during quick acceleration to keep the engine in its power band.

Common Issues and Reliability

Overall, the 8F35 transmission has not been associated with widespread catastrophic problems, especially when properly maintained; however, some specific issues have been noted, mostly in earlier model years.

Harsh or Erratic Shifting: Many owners report a harsh engagement when shifting from Park to Reverse or Drive, as well as noticeable or “jerky” shifts, especially between lower gears. This is often addressed by the dealership through a powertrain control module (PCM) software reflash or reprogramming.

Fluid Leaks/Contamination: Some units have experienced leaks from axle shaft seals due to excessive sealant applied during manufacturing. Additionally, debris or contamination in the valve body can lead to a diagnostic trouble code P0766 and issues like delayed or no reverse engagement, which can be fixed by cleaning the valve body separator plate.

Planetary Failure: Technical service bulletins (TSBs) have been issued for specific 2019-2021 Transit Connect vehicles with the 8F35, addressing transmission slipping and planetary gearset failure concerns due to potentially faulty needle bearings.

Regular maintenance, including checking and potentially replacing the transmission fluid every 30,000 miles (more frequently than the manual suggests to some owners), is recommended for long-term reliability.

Specifications