<hr style="color:#D1D1E1; background-color:#D1D1E1" size="1"> Hi Guy's this is my first post, hope it's as good as all the rest, I'll try and make it interesting...

I have an old Uhaul yep, I don't know why... It seems its the 4R100 tranny non pto of course and 2wd version.

I drove down the rd. after bleeding the brakes, new caliper front right, came home let it idle for about 10 min, shut her down.

Went to move it about an hour later, it went into reverse no problemo, then when put it in Drive it revved like it was in neutral.

There was no banging, no clunkin, nothing to make it seem like something catastrophic happened.

I then did a line pressure test and Reverse was fine 200 psi for sure, in drive mode however it was low like around 50 but had to rev real high to get it to 150 like 3/4 pedal and it would want to seem to go forward at a crawl but nothing more.

Next I did the obvious and cheked the fluid, it was about 1/4 quart low so added a bit. The fluid did not stink and was beautiful red like new.

I then tried again... no dice same scenario.

Then took off the pan, no metal chunks and virtually no dust on the magnet???

ok so I figure maybe something with the shift valves? Took them all off and the accumulators as well, all check ***** were in place and all valves moved freely.

Now onto the the solenoid pack, checked all per manual for ohms and all were perfect reads at about 27 Ohms, except the EPC solenoid that is the big one on the pack, it should read about 3-5 ohms but this guy is about 12.5 ohms.

I spoke to a tranny shop in town and they said it would not be the EPC and that I could "unplug" the solenoid pack and It would still move forward without it but not to drive like this as line pressure would skyrocket?

Im on a tight budget and working on my back. I am willing to take the tranny out and bring it into town but thought someone might have a few suggestions before I do that?

Personally I think it's electronic but I don't know ...

Why THis thing would have 200 lbs pressure for reverse and so little for forward I mean? that should mean that the pump is working great, if there was a broken something metal I figured I would hear something rubbing or banging or see some shavings?

Can this be a "worn out" valve? or gasket issue? all the check ***** are in place and "seem" good...

I really want to avoid removing the tranny at all costs so if there is something I am missing let me know and if you think just yank it out I will.

THanks Guys for any help you have, my family appreciates it very much.

Dave

 

If the forward clutch wasn't wiped out, that test probably killed it.Revving it to get it to go is the surest method of destroying a clutch.

I figure you're wrong and this won't fix it. The shift valves are not involved with engaging first gear.

You're getting colder. Solenoids can't do that.

They are right, except you CAN drive it like this, just do NOT put the shifter into 1. That will blow the forward clutch apart. Guess how I know this.

You could check the feed bolts. They are under the valve body. When they loosed it causes a large pressure leak and you can get this problem.

If you want I can list everything electronic that is related to the transmission. You can then spend a few grand and replace all of it. You'll still have the same problem because nothing electronic can cause this.

It means you have a large leak in the forward clutch circuit. It could be the feed bolts, or if the bolts are tight then the forward clutch seals have failed. Neither of these problems would impact reverse, so it will still operate normally.

 

Hi there Mark, Thanks for your reply.

I will be taking out the Tranny this week and let everyone know what it actually was. I guess the Forward Clutch seal is what makes the most sense at this time with no metal and or rubber found anywhere. I checked all the valve bodies and Accumulators etc.. no signs of any cracks those bolts you mentioned are tight so that I guess cannot be it and I am not sure how they could work themselves loose in any event. I do know however that after doing all this work it makes more sense to rebuild what I have as opposed to throwing in something used from god knows where.

Thanks for your 2 cents worth and I'll post some pics up with what we find this week.

There was no Transmission faults stored in the obdII whatsoever which I still thought was peculiar but who knows...

Thanks again for any help and input.

Dave

 

Did you drop the valve bodies, separator plate, and gaskets? The feed bolts are above valve bodies and cannot be seen, or accessed, without their removal.