@ArtMan

Compared with the ZF torque converter the GM unit is very straightforward to remanufacture so I think you should assume, for now, that your replacement unit is functioning correctly in response to the hydraulic pressures it’s being fed. The stator has an amount of free play (both axial & radial) so I think we should also assume that’s the internal movement you noticed.

The reason the 5L40-E torque converter lockup clutches fail in the first place is that wear in the valve block allows the spool valves to leak and therefore the hydraulic pressures drop off allowing the LUC to slip. If you’ve simply replaced the TC you may have fixed the symptom but not the cause. Did you fit a replacement valve block or have your existing one checked during your rebuild?

It would certainly make sense to check the TCC/PWM solenoid valve – particularly to see if the screen is damaged or blocked in some way.





Another cause could be the TCC control & enable valves which are mounted in the oil pump cover



but clearly it won’t be possible to check them now the transmission is back in the vehicle.

I think you’re right, therefore, to concentrate your efforts on the TCC/PWM solenoid valve first.

Phil