clunk going into 3rd gear (4l60e)
 

anyone know what would cause this? The trans the trans has about 8000 on the rebuild. The clunk only happens at low rpm's going into 3rd and downshifting from 3rd to 2nd. Their is no other issue other than the clunk. When im racing it doesnt do it at all. Tune problem?

push the clutch in the rest of the way?

Its a 4l60e..

+1

Likely driveline lash exaggerated by light loads and firm shift. The problem is, if there is a lot of "mechanical" shift pressure from the shift-kit, it can be hard to soften it up enough using software. I have a similar issue with mine and it is very difficult to get rid of without causing a potential wear problem .

Thanks jaime, do you think maybe going a little higher in stall will help reduce the problem?

A 1/4 ton of nitrous will fix the problem. :mrgreen:

what about a broke motor mount?

had a FerD do that when the converter locked for some reason. KLANK

pop hood, stand to one side, have someone hold it in gear, and gently rev it in Reverse & Park to see how much motor moves (dunno if that works, was always told it did...)