My mechanic just installed my GM motive 3:73 Gears with eaton posi differential, we put all new bearings in and the ratech install kit, my mechanic is really good, has done about 75-100 rearend installs.
We took the car out for a test drive and when we excellerate everything is fine no whining, when he lets of the gas and lets the car coast, The winning starts and is loud, My mechanic seemed very mad about it and has some possible ideas, BUT I am just curious what you guys think.
I need your help ASAP he is coming back over tomarrow moring

 

I have heard of this happening before. I'm not real sure, what to do because it has never happened to me though. Just have him set up the gears again.....

 

the pattern isnt right (could be the backspacing.) When you set them up, you have to rotate the ring gear both directions with the marking compound on to see the drive side pattern and the coast side pattern. I would bet the backspacing it a little off. IMO


let us know how it turns out