intermitent harsh shifting E4OD

Mekanik · June 28, 2008

I'm working on a 1995 F250 that has a intermitent harsh shift after the truck gets hot. First I need to mention that I am very new to the whole auto-trans stuff. This vehicle got a re-man trans about a year ago, the fluid looks good, no dtc's. I personally have put about 100 miles on the truck with no problem. The customer states that the problem occurs after driving 20 miles and then it shifts really hard into every gear like it has full line pressure. We have had people at my work drive it 45 miles with no problem. My service director verified the problem with the customer when he first came in and then yestrerday he got it to happen agian and he said that fluid started pouring out either the bell housing, the vent or the dipstick tube. I have not had time to look at the truck agian. I was thinking it might be a TP sensor or a VSS or PSOM acting goofy, but that dosen't explain the trans fluid pouring out. I would really like to take this thing apart and get a E4OD under my belt, but the last thing I want to do is take it apart and find nothing wrong. What if it has a faulty EPC solinoid? I won't be able to actually see that.

I have been told by a trans guy a long time ago that if fluid is coming out the vent or the dipstick tube, then it is "fucked". Any ideas?

GregH · June 30, 2008

If fluid starts pouring out, then it isn't necessarily fucked... I assume you're topping it off after these events, right?

I would expect the fluid is getting too hot. The torque convertor seal will start to leak with hot fluid, but it will usually seal back off when the fluid cools.

Harsh shifting is a default condition when the fluid gets above a certain temperature. The tranny is trying to keep itself cool by eliminating as many sources of heat as possible - minimum shift time to minimize clutch slip.

Inspect the transmission cooling system. Reman was installed? Did it get a new OTA? Are the lines bent up? Is there an inline filter, and is it installed properly? Why was the original tranny replaced? Were the lines and radiator cooler flushed?

Also, remans aren't perfect - new doesn't mean good.

First step is a visual inspection. Second, do a cooler flow test. I would expect you'll find a problem there...

Mekanik · July 5, 2008

Greg, I'm sorry that I have not responded sooner. I didn't get a chance to even bring this truck inside until this past Wednesday. Thanks for the help.

If fluid starts pouring out, then it isn't necessarily fucked... I assume you're topping it off after these events, right?

It only happened 1 time, while my Service Director was driving the truck. When the truck came in the trans was a little over-filled, but I just left it alone.

I would expect the fluid is getting too hot. The torque convertor seal will start to leak with hot fluid, but it will usually seal back off when the fluid cools.

I think the converter seal will be ok. I wiped it off and it dosen't look like it is leaking anymore.

Harsh shifting is a default condition when the fluid gets above a certain temperature. The tranny is trying to keep itself cool by eliminating as many sources of heat as possible - minimum shift time to minimize clutch slip.

[color:#FF0000That makes perfect sense. Thats the theory that I'm going with.

] [/color]

Inspect the transmission cooling system. Reman was installed?

Yes.

Did it get a new OTA?

No.

Are the lines bent up?

No. Is there an inline filter, and is it installed properly?

Why was the original tranny replaced?

I forgot to ask.

Were the lines and radiator cooler flushed?

I hope so, but I can't confirm this.

Also, remans aren't perfect - new doesn't mean good.

First step is a visual inspection. Second, do a cooler flow test. I would expect you'll find a problem there...

Yes I did. The cooler flow was 16oz. in 15 seconds. The spec is 32 oz. in 15 seconds. The flow improved to 24oz. in 15 seconds after I replaced the inline filter. I eliminated the ATO cooler without any change and I made sure the trans itself was producing enough fluid. When I disconnected the line coming out of the trans it produced about 32 oz. in about 7-10 seconds. The cooler in the radiator is clogged. My Service director wants to get the problem to happen agian while monitoring the TFT pid. Since the cooler flow is better I have a feeling the problem won't happen agian. The problem here is everyone including the customer was under the assumption that it is going to be a warranty repair.