I am noticing a clunk coming from the rear end of the car as the tranny downshifts. It is most noticeable going from 4th to 3rd and 3rd to 2nd. The car has recently been supercharged so the shift points have been changed. Is this normal or should I be concerned?

 

Mines always done it since I first got the car especially when going downhill I never worried about it I figured it was just drive line clunk or something.

 

not sure what is causing it, but that doesn't sound right. mine shifts up and down smoothly as far as i can recall.

 

The shifting is still smooth but now there is a noise. I can hear the clunk as it downshifts but the shift itself is still pretty smooth.

 

When the superchager was installed, I'm assuming you had a custom tune written for the car. Many transmission variables get altered such as line pressure, upshift points, downshift points, shift pressure, etc. You may want to speak with whomever wrote the tune to see how that would affect your car.

My 07 GT automatic is supercharged, as well, but no noises in my driveline. I had a great, local dyno tuner do the tuning for not just the supercharger, but also all the transmission variables, as well.

 

stock driveshaft still?

 

I have never noticed any noise like that when mine shifts. Keep up posted on what you find out.