I have a 95 Formula Firebird M6 and when I'm going down the hwy and let off the gas I can feel and hear this vibration coming from what I beleave to be the bottom of the car. I still have the stock driveshaft on the car. Would this maybe be a bad d/s or a prob w/my rearend ? I don't beleave there is any wineing coming from the rear, so what do you guys think ? Also, I had herd one time there was a recall on the d/s's for our cars and GM would replace them w/1LE d/s, is this true ? thanx for your help !!

 

Are you using an adjustable T/A? If so, your angle needs adjusting.

 

what you need to do is check to make sure the driveshaft isnt bent but it sounds like it is. To check, take out the driveshaft, and place it on a flat surface like a table so you can roll it. If it doesn't roll smooth then it is bent. Recommend the aluminum driveshaft from gm if it is bent. Also check the tranny mount that could be a problem.