After a few performance upgrades (Lid, filter, and Magnaflow muffler) there is a clunking when going WOT at each shift like someone is banging a hammer underneath the car. The car was bone stock before and did not have this problem. There was a noticable SOTP difference after the install. Any ideas? Is my tranny about to go? It's a stock 4L60e by the way.

 

Tranny mount?

 

is it a transmission sorta noise...like does it clunk when shifting or just clunk at WOT. Is there anything loose under the car? Id check the trans fluid before anything.

Thats all i have for advice..im not so good with transmissions.

 

It's just at WOT. Otherwise it is like normal.

 

well from the sounds of it i wouldnt say a bad transmission....someone with better experience could correct me if im wrong...but i think that you have something thats flopping around under there under heavy throttle...could be a tranny mount....check for anything loose under there....my bet is something is just flopping around wacking something under the heavy acceleration.

 

ya prob tranny mount...mine did that...get under ur car look at the mount u can usually look at it and see that its cracked/broken... its just a 25$ part thats pretty easy to fix

 

my car did this once... it was my exhaust even though it sounded like it was coming from the tranny... Check your clearance just in case,

 

My catted y pipe bangs under acceleration. Looks like yours is stock though. Probably the tranny mount.