Sorry to put up a spam post but I have been trying to find this answer and haven't yet.
I have 07 LBZ 4x4 with the Allison.
I'm getting the classic P0721 Output Speed Sensor Range/Perf code, but not all the time. Transmission sometimes locking in 4th, sometimes shifting crumby, sometimes wont go into reverse. replaced the output sensor on transfer case tail housing with no change. fluid and filters for tranny. my carrier bearing grenaded on the highway, and also while living in alaska the fan shroud essentially fell to pieces due to the cold.
so i know the TC could be torn up due to the wear from the driveshaft, and the TCM could be bad since it wasnt mounted properly for a while.
how can i diagnose? check wire 17? which wire is that? whats the best way to diagnose the TC? it still shifts into 4h, 4l, 2h, and neutral just fine.
apologies for my ignorance, but I don't know any duramax guys or shops in my area to ask these questions to, and im no master mechanic.
Thanks for any feedback
I have 07 LBZ 4x4 with the Allison.
I'm getting the classic P0721 Output Speed Sensor Range/Perf code, but not all the time. Transmission sometimes locking in 4th, sometimes shifting crumby, sometimes wont go into reverse. replaced the output sensor on transfer case tail housing with no change. fluid and filters for tranny. my carrier bearing grenaded on the highway, and also while living in alaska the fan shroud essentially fell to pieces due to the cold.
so i know the TC could be torn up due to the wear from the driveshaft, and the TCM could be bad since it wasnt mounted properly for a while.
how can i diagnose? check wire 17? which wire is that? whats the best way to diagnose the TC? it still shifts into 4h, 4l, 2h, and neutral just fine.
apologies for my ignorance, but I don't know any duramax guys or shops in my area to ask these questions to, and im no master mechanic.
Thanks for any feedback
