Got a question, I'm getting a thunk somewhere from under the truck when I come to a stop. I know could be anything but I've had the trans rebuilt (c6) new U-joints carrier Bearing, motor mounts seem solid tried revving in gear and no movement on the engine. Did notice today that the trans mount seems like it might be shot. Seems to not want to kick down when it should, could this be a kick-down linkage deal or what? Is there an adjustment on the linkage? or could the trans mount cause this? Not sure if I should take it back to tranny guy or what, the trans was rebuilt in September last year it seems to shift fine once I'm going but if I put the hammer down it doesn't want to down shift. Not real sure where to go from here, any ideas guys?
Thanks
Rob

 

My guess is that it "sounds like" a loose tranny mount; allowing some tranmission movement and binding the linkage.
The 'thunk' is the trans moving up/down on the mount. I'd check the attaching nuts at the trans mount first.
BarnieTrk