lakeffect2

I just had a 4l60 rebuilt by an local shop. After installation the engine runs but immediately stalls when going into reverse or forward from either park or neutral. The only way found to move it is rev it up and dump it into gear. Once moving it shudders to a halt when coming to a stop.

It feels identical to having a manual transmission and forgetting to put in the clutch when coming to a stop.

I think the converter clutch is permanently locked up.

I've read elsewhere that the likelyood is either the harness is shorted and therefore is grounding the ECM signal, causing the solinoid to throw the "valve" to lock it up TCC slider valve has been put in backwards,

Or that the spring(s) are on the wrong end of the shaft, pushing it in wrong direction regardless of solinoid operation.

The shop denies any responsibility that it could be their fault that a tranny malfunctioning that was just rebuilt by them could be the problem. "Must be a driveability issue the way I programmed the ECM" after a fresh motor rebuild (for bearings) even though it was the same program running the motor as before the rebuild.

Your input, thoughts and ideas from past experiences would be most welcome.

Dave Buchholz Rochester NY

jmd

iTrader: (4)

A ground is easy enough to check for.
Unplugging the connector from the trans. and driving it allows you to rule out the ecm tune.
It's possible for the internal wiring and switches to have been done incorrectly.

sofakingdom

iTrader: (1)

Also possible for there to be a hydraulic problem, with the solenoid valve itself, the gaskets & seals & O-rings around it, etc.

As jmd said, unpug the plug. That kinda splits the system in half: outside the transmission (problem goes away) vs inside the transmission (problem persists).

Logic is your friend. Unplugging something is always the easiest troubleshooting method. (well, almost, anyway...)

RBob

iTrader: (1)

Either the torque convertor is bad or there is something wrong internally within the transmission. The reason is that the TCC solenoid is fed from the 2nd gear oil feed.

This is why a properly operating 700R4 won't lock up in 1st gear even if the solenoid is activated. There isn't any oil being fed to the lockup solenoid.

RBob.