48RE - line pressure when in neutral

I have a transmission that when placed in neutral, line pressure drifts up to around 25 (5 lbs per second or so) and stays there regardless of throttle position. It is enough pressure to cause the rear clutch to apply enough to provide forward movement of vehicle. Pressure jumps to 85 when in drive and 0 when in Park.

What could the problem be?

Misalignment of the manual valve or leakage around the manual valve in the valvebody?

Anything else cause this scenario?

Reverse works fine as the reverse position of the manual valve dumps the excess pressure from the rear clutch circuit. So that kind of rules out a mechanical failure (binding or welded rear clutch pack).

Call Dave at goerend!

Anyone?

I'm waiting for a call back from Dave (I'm sure he's busy). Just looking for a little reassurance before I drop the valvebody again looking for the issue.

What Manual Valve is in it?

John

It is a select shift valve body from ATS using the standalone PCS controller. I used the term "manual valve" referring to the Dodge Service manual description of the manual valve which directs the hydraulic pressure to the necessary ports.

I've never had a manual valve removed from it's bore. Does it have a sealing ring of some sort at each shoulder?

Where are you checking psi? Cooler lines or Middle psi port on right side?

Should never have line psi in N.. Will kill 1st gear clutches.

Will see psi in the cooler lines in N..

middle psi port on right side. It should be zero in neutral but it isn't, that's the issue.

I assume it is only an issue if I let it run sitting in neutral (as the rear clutch is slipping). As long as I don't use neutral it shouldn't hurt anything, I think. It has good pressure when in drive and zero in park or reverse.

If it was a stock VB i would say your missing a check ball.. Not sure on that VB.

interesting...

More details to follow as soon as I get back, gotta run.

This all started when my torque convertor sheared off one side of the snout which drives the oil pump. This ruined the oil pump and took out the seal which caused a big leak.



I pulled the trans and wanted to go thru it to ensure it wasn't full of crap from the oil pump damage. A friend that does alot of trans rebuilds helped me go thru it and it looked good inside. Valvebody was clean, no particles anywhere. He noticed there were very few checkballs in the valvebody and questioned it. Based upon how it shifted prior to this carnage, we decided to add some checkballs to the valvebody to soften up some of the gear engagements. It was very harsh before, just going into D or R was almost violent. OK for a race truck but this is my wife's vehicle...

So some checkballs were added and everything was reinstalled. The Goerend triple disk was not sent off to be repaired yet, so a single disk was installed in it's place.

Truck drives great, shifts were mellow, D and R engagement was great. Except it has creep in neutral. I called ATS and explained the situation, the guy on the line said it should only have 2 checkballs in the valvebody (and explained which ones) and that is my problem.

So, I pulled the valvebody and removed the extra check balls from it. Reinstalled and have the same issue. This is when I put the gauge on it and watched the pressure to see what it was doing.

I don't put alot of faith in the info from ATS as they have never seemed to be able to answer my questions in the past about this VB or controller. But my hands are tied as I need the standalone controller...