i just bought a 2000 gmc with high miles from a guy about to go to prison. Yesterday he told me the trans went out and i could get it cheap. The body is pretty decent on it and so is interior. It has a 4.8 and is 4x4. The trans has first and reverse. Does not even attempt to go into 2nd gear whatsoever. i ran it out to 5500rpm's in 1st and left off and everything and still stays in first

Originally, there was a CEL for solenoid a. I forced it on and off a few times with efi live and it was clicking as it should. Selenoid b clicked as well. I unplugged the harness going into the trans as i read that should make it start in 3rd gear. I unplugged it and it still started in 1st gear. I am assuming that there is a problem in the trans internally then correct?

 

Obviously yes....