A buddy is having the following symptoms on his 2001 2500HD 4wd Duramax / Allison:
-Service engine soon light
-ABS light
-Parking brake light
-No speedometer function
-No reverse
-When I put it in drive, I think it is in 3rd (whereas when it failed on Sunday, it stayed in low)
He recently cleaned what he thinks to be the speed sensor (on the output housing of the transfer case) but it did not appear to be dirty at all. He recently replace the neutral position sensor.
He just bought a code reader and I'll post as soon as he has that info.
Thoughts, ideas, suggestions?