I have a 94 b4000 and my transmission has started acting up. I was driving it and stopped to make a turn and when I started going again it didn’t want to shift out of first gear I had it up to 3500 rpm’s and I left off and the rpm’s went down to 1500 and it finally shifted. All the other gears seem to work fine. Sometime it will slam in or out of first gear when it doesn’t want to shift.

 

did you ever solve this

 

Yes, pulled pan to inspect fluid and found a lot of metal flake and a piece of the clutch band in the pan. Put a good used transmission in and that fixed the problem.