TH400 No Pressure in Drive...
 

Turbo 400 transmission was working fine, then was slow to engage after being in park, then began slipping. Then stopped pulling in forward and reverse all together. The following is the results of my pressure test.

Test with no vac and 1000rpm:
Park: 110-120psi
Reverse: 0 (occasionally will climb to 5)
Neutral: 110-120psi
Drive: 0
Second: 0
Low: 0

Fluid level is perfect. Modulator is working. Governor is fine. I pulled the governor cover and removed the governor and started the car to make sure it was pumping fluid into the governor and it was.

Any ideas? Is there anything a torque converter can do to cause this?

Hmmm... got any specifics? Trans brake?

Guessing with out any hard info I would head for Band servo ;)

I rebuilt it from a mid 70's model 1ton pickup core with factory deep pan. I did a completely stock rebuild on it and did not alter the valve body at all. I even put all the check balls in even though I usually only do the front and rear... I do not know the history of the core but it did have a stripped out governor gear on the gov. when I got it. When I first installed it and hit the road with it, it was working great. I stopped to get gas and started it up and it worked fine again. I then stopped at Wal-Mart and when I came back out and started it, it was slow to engage in Reverse and in Drive. Then when I pulled out on the road it began to lightly slip. It then started slipping worse until I lost all forward movement. The strange thing is, if I turn it off and set for 2 or 3 minutes and start it again and put it in Drive it will pull forward for 30-40 seconds before slipping out of gear completly. (yeah, it took me for ever to get it home this way, but it saved me from having it towed.)
Now, setting in the garage I got the above pressure results. I was very gentle with it the whole time but it does set behind a 383 stroker with a 6-71 on top. Any idead? BTW, thanks for the fast reply!

Time to pull the pan. It "Sounds" like you have a clogged filter.

Then againhow was the govenor bore? Did it need bushed? even at that you should get movment just no shift.


very odd Issue with those PR readings

Make sure the manual linkage is all good and the retaining nail is in place.

feel free to E-mail me

Well, darn it, it was the filter. I was convinced it was something complicated. This was the 3rd time I had had this tranny completely apart to try and figure out what was going on. I air checked everything and went over the whole dang case with a magnifing glass looking for cracks. I even made a couple of homemade tools to test some parts as an assembly. Turns out my freakin brand new filter was flawed. The filter material got sucked up into a big fat wad by the filter neck and was not letting hardly any fluid get through. I don't know how you were able to tell thats all that was wrong just by what I described but thanks a million man. I owe you one.