| | TH400 intermittently will not 1-2 shift
The TH400 in my 90 Chevy dually wont shift intermittently. When it gets stuck in 1st i have to drop it into manual 2 then it will shift up to 2nd and then usally move the shifter back to D.
I've pulled the governor off took a look at it, the springs are ok, weights seem fine and the plastic gear looks like new. Only thing im not sure is if the piston in the governor is getting stuck or if that is even possible.
The vacuum modulator is brand new and i've checked it couple times and its fine.
I removed oil pan and checked the filter, and it looks fine.
The transmission fluid level is fine.
If anyone has any suggestions that would be great.