GM's 10Sp Tranny Debacle

[Outnumbered]

Any of you fellow OTT folks had the dreaded valve body/solenoid failure on your 10 speed transmissions? I was heading back from a week of vacation with family and dog with a truck full of gear and about 2hrs from home in a very busy place, the trannny went to hell and into limp mode. I finally got it to a safer place and then discovered I could limp home with no reverse by limiting it to 6th gear and staying at 50 or slower. Had it towed to the dealer Tuesday and they said it will be at least a week before they can get the parts but I am starting to think that was a canned answer as looking online this appears to be a significant issue for GM with people reporting weeks to months getting parts for both the regular and even the HD Allison transmissions. Three years old and only 45k miles so it will be covered under the powertrain warranty and they are still trying to get me a loaner/rental.

 

[RBsingl]

The 10 speed HD isn't really an Allison, GM paid a licensing fee to use the name unlike the prior 6 speed used behind the Duramax which is an actual Allison. The 10 speed Allison is just another closely related variant of the 10 speed used in cars and light pickups by both Ford and GM.

The class action lawyers are going to have a field day with this screw-up because the valve body issue has been known since shortly after this transmission was put into production and GM added the monitoring software to provide a warning before the output shaft lockup occurs and continued using the same part without revision.

Fortunately my pickup is a 2018 with the real Allison but I have a Cadillac and a Chevrolet with the 10 speed bastard offspring from the JV between Ford and GM to develop transmissions. The 2024 Cadillac had the monitoring/limp software installed as part of production, my 2021 has to go in for the recall to add the software. GM extends the warranty to 10 years/150K because of this issue.

There are properly designed aftermarket valve bodies for the 10 speed and if you are keeping your pickup long-term, that might be a consideration but that would kill any GM warranty on their little failed experiment.

Rodger