The two most iconic American vehicle manufacturers are competitors and yet still partners. As economic instability motivated companies to find ways to increase efficiency and meet new governmental fuel economy standards, Ford and General Motors have found it beneficial to work together. This has occurred a few times in the last 20 years but often on the most complex vehicle systems. It is not surprising that transmission engineering became a target to join forces.
A few years ago, the two companies agreed to share transmissions for use in their domestic products. Ford shared its new 10-speed transmission with General Motors to use GM’s new 9-speed transmission in select Ford vehicles. The 10-speed transmission is intended for longitudinal (rear-wheel drive) applications, whereas the GM unit is for transverse (front-wheel drive) usage. The 10-speed has been used in Ford’s F150 pickups and Mustangs, while GM has used it in their Corvette and Camaro and their larger SUVs.
As befitting any great rivalry, Ford decided that the GM 9-speed offering wasn’t quite up to their standards and opted to make some changes. Ford has introduced two 8-speed transmissions, one based on the GM 9T and the other a rework of a 6-speed transmission that GM and Ford partnered on back in 2002. Ford felt that the GM 9-speed did not improve enough fuel economy over existing 8-speed units, which has undoubtedly been seen with GM automobiles using the new 9-speed. For instance, the 2017 Chevy Malibu with the new 9-speed transmission gained only one mpg on the highway over the previous model’s 8-speed. The 2019 Buick Envision actually lost one mpg over the previous model’s 6-speed automatic transmission!
With that in mind, Ford significantly changed the base GM 9-speed transmission. Where GM had focused on drivability and smooth shift transmissions, Ford decided to focus on improving fuel economy. The result was the 8F35 transmission.
The 8F35
Ford decided that there was no real advantage to having nine speeds, and the extra gear added weight and cost that didn’t improve fuel economy. Essentially, Ford decided to remove the 4th gear, among other adjustments. These changes made the 2-3 shift step very small, and the transmission acts as a 7-speed under most driving conditions.
Ford also decided that they would use several design features they had used in the 10-speed platform. Borrowing the 10R torque converter saves space and weight. Still, it is a more complicated unit to control because it applies the torque converter clutch toward the impeller assembly rather than the cover. Ford also redesigned the valve bodies and the oil pump assembly to use the same software platform used by the 10-speed unit. This saved weight and reduced the number of valves needed in the system. It also borrowed parts already in inventory for the 10R transmission.
Some Problems
The 8F35 is too new to be seen frequently in transmission shops since it is still under the manufacturer’s warranty. However, Ford owners should be aware of the following complaints about the units. Most of these issues deal with harsh or erratic up and downshifting and a noticeably hard engagement when going from park to reverse, park to drive, and from reverse to drive. This can be caused by a Power Control Module (PCM) problem, and a Technical Service Bulletin has been issued. Here you can find a copy of this TSB.
Other owners have reported issues with low-speed surging and inconsistent acceleration. The 8F35 does use a computer-controlled adaptive learning system, which means that the system “learns” from your driving style and adjusts shift points. Further driving might make the problems go away, or it might need reprogramming. The increased use of computers, sensors, and adaptive characteristics has contributed to the complexity of designing, maintaining, and repairing these driveline systems. This increased electrification of transmissions is a trend to stay and another reason to trust transmission specialists for transmission maintenance and repair services.
For now, these issues will be handled under the manufacturer’s warranty with service provided at the dealer.
Ford Transmission Experts
If you drive a Ford vehicle with an 8F35 transmission and have questions about its performance, give us a call! The Advanced Transmission Center team consists of technicians who have decades of experience diagnosing, rebuilding, and repairing transmissions in Ford cars, trucks, and SUVs.
If you are having problems with your transmission or any other driveline-related issue, contact Advanced Transmission Center at either of our locations, and we’d be happy to help! We’re your local transmission shop. Unlike dealerships or many independent repair shops, we are transmission specialists trained to fix vehicle drive-train issues. You can reach out to whichever location is most convenient.
Additional Considerations
How does the 8F35 transmission compare with Ford’s previous transmissions in terms of fuel efficiency and performance?
The 8F35 was designed to improve fuel efficiency over its predecessors and competitors by simplifying the gear set and using advanced technology borrowed from the 10-speed transmissions, aiming for optimal performance with fewer gears.
What specific challenges did Ford face when re-engineering the GM 9-speed transmission into the 8F35, and how were these overcome?
Ford aimed to enhance fuel economy without compromising drivability. The challenge was to reconfigure the transmission to remove unnecessary complexity, which was achieved by eliminating a gear and employing a more efficient torque converter and valve body design.
Advanced Transmission Center is a Colorado-owned and operated auto repair shop with locations in Denver / Lakewood and Westminster. ATC specializes in driveline issues such as automatic transmission repair, four wheel drive repair, clutch replacement, differentials, manual transmissions and CVT. As Colorado's first AAA approved shop our goal is to provide accurate, timely service with exceptional customer satisfaction. All of our technicians are certified in the latest makes and models and we are one of the few transmission repair shops with a nationwide warranty.
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