also check and see if your exhaust is hitting ur drive shaft... mine is.

 

I had this same problem just get the buschur mustache bar and it will completely fix the noise and the whole rear end will fill so much more solid def. one of my favorite mods iv done also the car will launch better if u have a good amount of power but thats all u need.

 

i would stop power shifting till u get this resolved unless u want to drag your driveshaft on the floor with sparks behind u

 

Putting on a blox front motor mount didn't eliminate the issue but after adding the FP Red turbo I no longer clunk the diff when I NLTS at 8000rpm.

Last year, stock IX turbo, stock bushings, blox front motor mount it would clunk every NLTS shift to an 11.9 115mph.

This year, only chnage is I have an FP Red and now I NLTS to an 11.1 at 125.49mph and it never clunked.

Maybe because the red makes over 400hp to 8K and when I NLTS it makes similar power it doesn't upset the balance as much?

 

my car dips hard in the rear with weight transfer when it clunks like that.
stiff susp and that moustache bar will prob help

 

I get this all the time from customers, and i can bet my whole pay check its the rear diff. Replacing the rear differential bushings will take care of that "clunk" you are hearing. If you have any more questions feel free to call us, we would be glad to help!


-Cisco