:mad3:

So my 400 stopped shifting. I've replaced the modulator, and checked the govenor and still no shifting. I'm trying to do everything I can before it goes to a shop. I was thinking of checking the filter. Is it just a matter of taking the pan off and putting in a new filter? Transmission are like a forign language to me, but I'm starting to learn alot more about them. Pictures would be a great help...

Thanks in advance

did you check to see if the vacuum line to the modulator got unhooked on the intake manifold end?

changing the filter is dead easy. Take the pan off except two bolts on one end, pry the pan loose so its angled and all the fluid is coming out from one side. Take the pan off, look for debris or shavings in the pan. Thats bad, take off the filter, look for the spacer with the bolt. Dont loose it. Put new filter on with new o-ring. Using a new cork/rubber gasket, NO RTV, re-installed pan, torque and fill. Check for leaks.

When you say you checked the governor what do you mean? Does the drive gear look alright, did the spool in the center move up and down. Normally the governor DRIVE gear inside the tranny doesnt give any trouble (iirc its steel) but wilder things have happened.

Sounds like the governor isnt turning or the spool valve inside it is stuck.

Wish ya luck!!!

When you say you checked the governor what do you mean? Does the drive gear look alright, did the spool in the center move up and down. Normally the governor DRIVE gear inside the tranny doesnt give any trouble (iirc its steel) but wilder things have happened.

Sounds like the governor isnt turning or the spool valve inside it is stuck.

Wish ya luck!!!


The TH400 Governor gears are plastic... sadly. it might even look serviceable. if theres even slight wear, i would recommend replacement. youre right about the spool inside the governor shaft. to check for movement, hold the governor by the gear, with the weights under it. Gravity will allow the weights to fall in an outward position. by closing the weights, you can see if the spool moves. No movement, clean, clean, clean, see if you can get it unstuck.

did you check to see if the vacuum line to the modulator got unhooked on the intake manifold end?

No, but i still have vacuum

changing the filter is dead easy. Take the pan off except two bolts on one end, pry the pan loose so its angled and all the fluid is coming out from one side. Take the pan off, look for debris or shavings in the pan. Thats bad, take off the filter, look for the spacer with the bolt. Dont loose it. Put new filter on with new o-ring. Using a new cork/rubber gasket, NO RTV, re-installed pan, torque and fill. Check for leaks.

Sounds easy enough. How many ft pounds on the bolts??

When you say you checked the governor what do you mean? Does the drive gear look alright, did the spool in the center move up and down. Normally the governor DRIVE gear inside the tranny doesnt give any trouble (iirc its steel) but wilder things have happened.

Sounds like the governor isnt turning or the spool valve inside it is stuck.

Wish ya luck!!!

By that I mean I took it out and looked for wear on the metal.. apple coring, stress cracks, anything.

The TH400 Governor gears are plastic... sadly. it might even look serviceable. if theres even slight wear, i would recommend replacement. youre right about the spool inside the governor shaft. to check for movement, hold the governor by the gear, with the weights under it. Gravity will allow the weights to fall in an outward position. by closing the weights, you can see if the spool moves. No movement, clean, clean, clean, see if you can get it unstuck.

The weight for sure "opened" when i held it upside down, did the spool move? I dont recall. Sounds like i'll be pulling it back out. Thanks for the suggestions I'll let ya know what I find