I have a 1992 Chevrolet Lumina APV (3.1 engine) with the following problem:

Sometime, usually after the engine is at operationg temperature, I hear a loud "bang" like two clutched hitting each other hard everytime I switch into Drive from Reverse or Parking.

Otherwise the transmission works and shifts very smoothly but that noise really started to bother me.

Does anybody know what makes that noise and what it means?

Since it only happens when you change direction/load, I'd say its a sloppy CV axle joint. Rear wheel drive/4-wheel drive vehicles experience a similar situation when the drive shaft u-joints go bad, they will clunk or ping when going from reverse to drive to park etc...

I guess you looked at the engine roll restrictors on top?

You'd usually feel the motor slamming around on upshifts too if they are broke, though..

I'm pretty sure it's coming from the transmission housing (I'll check again this evening to be sure) and it only happens when I switch from Parking or Reverse into Drive with a hot engine.

On cold the switch goes smooth as silk with no audible noise whatsoever. That's why this loud "bang" when going into Drive after the engine has warmed up worries me. :runaround:

Perhaps the beginning of a torque convertor lockup that's dragging when warmed up....does it seem like the engagement hits unusually hard when you hear the sound?