ls1_driver43

My shifter rattles and shakes really hard when I get to higher rpm. This is after a rebuild but I never had the car before so I don't know if it shook before the rebuild. Anyways I changed the tranny mount with no luck. Could it be because I didn't shim it? If not what else could it be? Driveshaft? Tourque arm?

jmm98LS1

iTrader: (28)

Does it do it in every gear? If so, usually rpm dependent vibrations are caused by something in front of the transmission......like an imbalance in the rotating assembly, front accessories or the clutch stack. Could also be a misalignment of the trans input to the centerline of the crank (maybe a missing alignment dowel?)

ls1_driver43

It does in 1st and second i havent been able to check others as the car isn't licensed, so no highway. It wont shake in neutral or with the clutch in. The clutch to my knowledge has never been taken out so how would something be off balance? and how do you check the alignment of the input shaft? Lastly what do you mean by missing alignment dowel? Both dowels went in there holes fine. one looked like it might have been cracked but im positive it was just the way the anti seize looked on there.