Johansson

Hey there friends.

My truck started to act weird couples of weeks ago.
Heres what happens:
First thing: Straight forward when itīs in O/D, the lock up engages and the rpm drops but immediatly increases and then go back to normal, with lock up engaged. And itīs not just the lock up itself that slips, the engine runaways like if I put it in N and then back. Itīs just like it suddenly looses the oil pressure, causing the O/D or L/U to disengage.
Next circus act: When cornering (makes no diffrence if its left or right) either in O/D with L/U, O/D without L/U, 3rd with L/U or 3rd without L/U the same thing happens. It starts to slip heavily and wonīt engage fully until I straighten out.
In first or second gear it seems alright. (Spent the evening driving 600 laps around a parking lot while normal people sits in ther couch having a bloody mary or a nice cold beer. Funny how life turns out for some of us.)

I thaugt there was a tube down in the oil pan with a bad gasket or o-ring further up that would cause it to draw air in there while cornering (hadnīt explaind the straigth forward symptom though) but it turned out as many of you know, that the lift tube is cast into the valve body. The filter looked fine and the fluid IS at correct level. Fluid changed 10 months ago. And itīs anyways not the fluid that is the problem because the fluid doesnīt give a **** if you drive straight or cornering as long as it gets to the pump.
Is there a gasket between the valve body and the trans case that could have gone bad? Or the solenoids? One for O/D and one for L/U located att the valve body right? Still canīt see how cornering would affect them. Hope you guys have a little more knowledge and experience about these trannies than I do.

Mopar1973

As for the OD neutraling out under operation, there is a piston in the back of the case that actuates to engage OD and if the seal tears, it will lose pressure and act like it wants to neutral out because it can't build the pressure to maintain engagement.

Johansson

Okey, found out that it does the same thing in the lower gears. And when it has been standing for just a short while with engine off, itīs not taking off immediatley when i shift into D, like it did before. It takes a few seconds idling in N first, or hi revving in D to make it take off. Is it possible that my torque converter doesnīt get enough oil? Is there som kind of high pressure safety valve that could be screwing with me?

infidel

Install a lockup switch even if temporarily and see what happens.
It will tell you if the problem is electrical or mechanical.
It's cheap and easy.
Instructions> http://www.tstproducts.com/Torque%20...p%20Switch.pdf

Johansson

Already have one. Makes no diffrence. As i said, it acts just like it looses the oilpressure and it happens in all gears. Well, ainīt got time to play with it this week. Gonna do some experiments with it next week. Thanx for the replies! Some times I miss my -88 silverado with 3 spd manual that made my right arm twice as thick as my left one in 2 years.

gorms

I had a problem way back when I had the auto of slipping out of gear, but mostly just on left turns. Problem came on shortly (under 3k mi) after a fluid/filter and band adjustment, turns out it was a combination of a dented pan and dirty filter starving the pump at the right times. Never had that problem again after pounding the pan straight and keeping the fluid on check.

FWIW also, we used to have a 98 1500 auto that would drop out of gear randomly, but always at a stoplight. Filter/band adjustment made no difference, added some Lucas tranny-syrup and it still runs on the same tranny now, sold the truck 5 years ago.

jughead

simple test is add 2 quarts of fluid to the trans and try it. if it doesnt fix it u can drain it out. really sounds like the classic low fluid syndrome

Johansson

Already did! This morning I thaught, what the heck, Iīll try and overfill the trans just a little bit and see what happens. So I did, and what happened was that the trans worked fine. So I added more and more successively and at last Iīd added 3 quarts without any level increase on the dipstick. Gonna buy some more fluid and fill until I see a change on the stick. Thanks for your replies. Easy fix this time.

jughead

one more thing be sure to check in neutral idling