Ok, ever since the m6 swap ive noticed a RAELLY annoying and VERY pronounced vibration and buzzing after 85mph and it gets worse as speed increases. I thought perhaps it was something to do with the flywheel not being balanced properly, but it doesnt do this revving at idle or when holding down a gear and letting the engine speed to the same rpms as traveling at the higher speed (which also has me doubting it being anything in the trans, unless its possible something wrong with my 6th gear?!) could this be that recall i remember hearing about? time to visit gm? lol

Anyone have a clue as to what would cause this?

(for those that dont want to read, "bad vibes over 85mph")

 

Try getting your driveshaft rebalanced first.

Ben T.

 

For some reason i hadnt even thought about doing that.. can any shop do that or is there a specific kind of shop i should look for to balance it for me? or perhaps it would be just as cost effective to get a LS1 or 1LE driveshaft