96 f350 7.3 e4od. Torque convertor won't unlock in reverse or 1st after truck is warmed up, causing it to bog down and stall. Truck also shifts hard and slow if accelerating hard. I pulled the pan and found it had a 2wd filter in it. Replaced with 4x4 filter and added filter clips to hold it in place. Thought for sure this was the issue but its still going on. Would it need to be disconnected to relearn or anything? I know theres a ton of other electronics attached to trans operation. Brake and 3rd brake bulbs are fine. My icp wiring is an issue, truck runs but fluctuates slightly. I unplugged it and its stable. This issue didnt change when icp was fine, bad, or after I unplugged it (same time i replaced filter). Any other lights or electronics to check? Most issues Ive seen from other electronics just cause hard shifting, not this. Ive got the cash ready for a Sam Wyse stage 1 trans but afraid I'll get it and still have the issue because of some dome light not working.

 

It isn't capable of learning anything, so you don't have to worry about that.

Usually, this is caused by low line pressure. Get a 0-350 PSI gauge with a 1/8" NPT thread. Install it in the test port on the driver's side of the trans. Record pressures in each position at idle - PRND21 and post them here.

 

How will I get a reading if it stalls? I was thinking I could jack the rear tires off the ground.

This truck supposedly has a rebuilt transmission and heavy duty torque converter. PO said its been stalling in reverse since the rebuilt. It only does it when warm. Maybe the anti-tc lock protection? I used to could keep it from stalling with a little fuel but it wouldn't the other day. There was a couple times when the truck was warm and it didnt do it.

Before I buy a gauge, is there anything else I can check? I have replaced mpls. I pulled the filter and it was a 2wd filter, i swapped it out and filled it back up. Let truck idle for a good long time before trying to drive it, no luck. Even put it a quart over and still no luck.

My wild guesses (before i end up swapping a zf5)
Needs a tune to tell trans to give upgraded torque converter more fluid.
Plugged trans cooler. (Easy to check i guess)
Something electrical not telling computer its in Reverse, and to increase line pressure. (But i have no cel or flashing od light. Forscan shows nothing. I could probably tell what gear the computer is seeing through gear selector PID on forscan to rule this out.)
Or something with it needing to fill torque converter more by running longer since replacing filter and Im just reading the dipstick wrong? (Least likely)

 

If the pressure is heading down before it stalls that indicates there is a pressure problem causing the converter to drift on and stall the engine.

What in the world is anti-tc lock protection? I've never heard of that.

There is. Take the trans out and tear it down. Inspect all of the seals in the trans, use a micrometer to measure the pump to see if it's worn. I think getting a gauge is FAR easier.

That couldn't cause this problem.

That could have done it. Too bad it wasn't the issue.

Not possible.
That will make it run hot, but I fail to see how it would make it stall in reverse.
If that were true it would be less likely to stall in reverse.
If it hasn't totally filled the torque converter in the first minute that it's running the pump is totally shot and the trans won't work at all.

 

@ anti-tc lockup. I read the e4od doesnt lockup when cold to protect transmission. I imagine only in forward gears. It was me trying to understand why this is only a when-warm issue.

@ mpls. Its my understanding when you put transmission in gear, the mpls tells the pcm which gear its in, so it can tell the transmission how much line pressure to give.

 

It doesn't lockup cold to help warm the engine and transmission. Nothing would be harmed if it locked cold. The "anti-tc lockup is just some software that monitors trans temp and doesn't allow it to lock cold. That can't make it stall.

If there was a code for a failed MLPS it could raise line pressure, and that could create a stall condition. If there was no code then the MLPS wasn't involved in the problem.

 

Finally got around to putting a gauge on it. showing 55psi in all gears, with a fluctuating 90psi in R and 1. Goes up to as much as 130psi when shifted into R, then fluctuates between 80-95 until settling around 90. Isnt stalling right now, maybe it hasnt warmed up enough. Engine is almost at operating temp, but Ive just been idling. Usually doesnt stall when cold.

 

Those pressures are normal. Get it warmed up and try again. The trans will not warm up idling. It needs to be driven.

 

It'll have to wait until im back in town. I did go down the highway and get it hot. Aftwerward it nearly stayed running when in R. Nearly.

Something to maybe help diagnose. Truck doesnt idle backward. It just sits there until i actually give it throttle?

 

[QUOTE=Unsung;19659073Engine is almost at operating temp, but Ive just been idling. Usually doesnt stall when cold.[/QUOTE]
all your doing to the trasnsmission when idling is pumping fluid in it and not moving anything, so those pressures are from a COLD transmission. drive about 10-20 miles, park it and check pressures.

 

Sorry, been too busy to get it done. Warmed up completely driving down highway 40mi. Showing around the same pressures, just super erratic in R and 1. If I can keep it running it eventually smoothes out and stops trying to stall. Is it possible theres something not right in the valve body? A modulator or something.

 

It isn't likely, but anything is possible. I think it is more likely that some seals are worn and leaking. If I am right this will continue to get worse.

 

I read the possibility of bad or improperly torqued valve body gaskets causing issues. Im considering buying a transgo shift kit and putting it in and replacing gaskets. I think they're around $100? And if that doesn't work, Sam Wyse stage 1.

 

That is a possibility.

 

I've been having this same issue on a 94 with a 300 i6/E4OD. Bought it sight unseen on ebay from CA. Super clean truck and runs great but one day it died on me going into reverse, and now weeks later it did it twice in one day. I'll put it back in park, start it again, go to reverse and it'll SLAM into reverse hard af. The fluid looks quite old, kind of brown, smells fine, so I was going to start with changing all 18 quarts of fluid and a filter change. If you find the problem please post what it was. It only has 130k miles on it so I wouldn't think the trans should be too worn out. Has no codes. I've seen elsewhere on here instances of a filter change helping.