About 4 or 5 months ago the tranny would not shift out of 1st gear. The first thing I checked was vacuum and swapped the modulator. This did not solve the problem. Not knowing much about trannys I brought it to the local tranny shop and was diagnosed as a bad governor. They showed me the old part and it looked like a plastic gear on the end was broken. Now I am having the same exact problem again exept now its intermittent. So my questions are should I just replace the governor again and hope for the best? Is the governor easily changeable? Could there be other internal problems? Where can i buy this part? Thanks for any help.
Rob

 

Those darn govna gears be made of plastic =(

Maybe the spool valve deal is stickin....




This is showing the passenger side of a th400.

 

Two things for preliminary diagnosis of a T400 no upshift condition.

First is the modulator and vacuum line to it. Make sure it's not kinked or rubber line leaking.

Second is make sure the kickdown switch is not stuck in downshift position. On your car it should be underdash at top of the accelerator pedal. If it is not stuck, possibly the downshift solenoid inside the trans is bad. It can be accessed by dropping the pan.

If both those check out, governor is the next suspicion and is usually simple to get to. That silver square cover on bdub's pic is the governor cover.

Past that it's usually an internal problem. If you find that governor gear chewed up again, find out what's causing it.

 

Check the governor first. Make sure the gear isn't chewed up, make sure the bore the governor spins in isn't rough or scored.If the governor bore is rough it might be causing the governor to hang in the bore, making it hard to turn and chewing up the gear (also known as the apple cored drive gear). If the bore is damaged the trans need to come apart for a repair sleeve.

 

In addition to the simple/basic things already mentioned, check the torque on the valve body bolts. Twice over the years, I've run into no shifting or no drive because of loose bolts.

 

Thanks for all the input, much appreciated! I think i will pull the gov and see if its chewed again and check the bore. If it is I will replace one more time since it not an expensive part. Hopefully it will last the rest of the summer. if it chews again looks like I have a winter project.
Thanks, Rob