I have a 2005 Chevy Express AWD cargo that won't shift out of first gear.I had the van in for rear brakes and I get a call from the shop that my tranny is screwed . I dropped the pan changed the fluid and filter, replaced 1-2 shift solenoid , still the same , .... any suggestions .
Thanks

 

Any codes? I would get a reader on it. Speed sensor, Throttle position sensor, camshaft position sensor.......all play a part in shift points and info that the computer used to control the tranny.