t400 tranny problems

[thoughtpolice]

Hello all! Good day to you.


I have a 89 2500 4x4 with a 350 and t400. I have had a tranny leak since I purchased the truck not long ago. We replaced the pan gasket last week. Inside the pan it was really nasty, and it turned out the filter wasnt even properly inserted and was loose in the pan. However it was working fine except the leaking. So we changed the fluid, filter and gasket. Now its all messed up.

When I am sitting at a red light for a few minutes and go to take off, it revs up real high and the truck will hardly move for the RPM being used and it will wind out and do a couple of hesitating back and forth shifts up and downit feels like, and then it will go into 2nd and 3rd fine. The problem only happens when I either sitting for more than about 10 seconds or so or also occasionally through a slow turn like in a neighborhood. If I slow down to 1st gear then take off it will shift perfectly.

Any ideas?

[bigj-dog]

Sounds to me like you're low on fluid. I had a dipstick o-ring leaker that I never noticed since I park on gravel and it wasn't until I noticed it's hesitation into first gear that I started looking around. Put in a new o-ring and refilled the tranny and everything straightened out.

[roadrunner_70]

Your problems sound almost identical to the symptoms I was having. Do a search using "4L60E". Mine had to be rebuilt, with the only explanation being that the seals had possibly hardened, leading to a drop in line pressure. Also look for foaming of the fluid, if perhaps it was overfilled. I believe that the new fluid can flush out much of what may be keeping the transmission running properly. Definitely change your fluid as required, but if you bought the vehicle used, or don't know the history of the transmission or it's fluid, be prepared!

[jveik]

well, if worse comes to worse, you can always get one at the junkyards near you for probably 50 or 100 bucks and pop it in there. or get a freshly rebuilt one for cheap also, i think turbo400's around here run for about 475 bucks.