6-speeds seem to have been the sweet spot between engine efficiency and transmission durability. And much like how the removal of spare tires in many vehicles to get an EPA checkmark does not result in any appreciable fuel mileage gains, I failed to see any appreciable fuel mileage gains when vehicles went from 6 to 8, 9, and 10 speed transmissions. I look at the EPA mileage numbers before the swap and the mileage numbers after, and I'm not seeing any gains that were worth all the hassle.

https://www.youtube.com/watch?v=6tYTLq9QNGg


GM is having major issues on their truck 10-speed transmissions. Some notes:

- The half-ton 10-speed transmission was developed by Ford. The "partnership" was that Ford designed the 10-speed for trucks, and GM designed the 9-speed for mid-size SUVs and such.
- Once the basic design was complete, both GM and Ford proceeded to tweak and manufacture their own version of the 10-speed transmission.
- Both GM and Ford have had issues perfecting shifting patterns and how it contributes to the overall durability.
- Both took that basic architecture and went about designing a beefed up version for HD trucks.
- While the half-ton versions are still a lot alike between the two companies, the HD versions do have some major differences.
- That said, the internal components of the two HD transmissions still look very similar. Why? Because they both originate from what is basically the same half ton 10 speed.
- However, Ford went a little beefier and more durable on a few key components.

One silly thing that GM did is they have a decades long history of declaring their HD trucks have Allison transmissions. They did not want to lose that branding, so they pay Allison to state that Allison approves of the transmission, and therefore the wholly GM designed and built 10-speed HD transmission is called an "Allison (see the special note) Transmission."


It's funny to see GM guys all over the place trying to claim the HD 10-speed has absolutely nothing to do with the half ton 10-speed, and that the HD transmission is an Allision Transmission, but that half ton transmission is a Ford piece of crap. Well, joke's on them cause the basic concept and design of their GM tweaked and built but Allison tagged transmission is still the Ford design at heart.



Really wish they'd scrap the 10-speed nonsense and go back to the 6-speeds that worked great.