I had my driveshaft re-balanced this today, it was built 2 years ago when I first went to a th400. They had to move the weight about 1 inch and had to add 10grams of weight to the yoke end of the driveshaft. Will it being out of balance by 10 grams cause much of a vibration? I was getting a little vibration right before the 1000ft mark and losing a little fluid out of the tailshaft, trans was just freshened and had a new bushing put it in the tailshaft housing, so thought I'd have it checked out. No vibration driving on the street at 55-60mph.

it's all those wheels up launches Bob. might have twisted it a little.:D

mike

No twisting was evident, although its a wonder, with a stock, shortened driveshaft :D. I was curious as to whether the experts think 10 grams caused my vibration or the fact that I lowered the rear of the car 1" after having new gears installed in the rearend. There is no evidence of vibration til I near the end of the track. TIA

10 grams will make it vibrate. So will yokes not being in line with one another, like GM made some of their drive shafts in the 60's. They claimed it made up for engines sitting off center, as I recall. Had one in my Camaro and it vibrated until I had the yokes lined up.