[crustysarge]

I have been chasing a high speed vibration problem on my 77 TA and am pretty depressed on the progress. Car is a factory 4 speed that I converted to TKO 600 and 3.5 aluminum driveshaft. Rear end is a 10 bolt 3.73 with Eaton posi and Moser axles with disc brakes adapted from a LS1 98 TA.

Vibration comes on around 85-90 mph and you feel in the shifter and seat of the pants. Bad. Stays until speed drops down to less than 70 and stays on decel or clutch in/out, makes no difference, once it starts the only way to stop it is to slow down. Car had this with original trans and D/S also but I rarely got to those speeds with the 3.73 gears.

I have a pit so I set car at ride height with rear end supported at ride height with tires off, rotors off and it vibrates the same while running up to speed. Today I measured drive line angles have trans pointing down 2.8 degrees, D/S pointing down .10 degrees and the pinion is pointing down 1.7 degrees.

I have also found the shaft is actually hitting the pinion yoke and u-joint strap bolts, see pix. Not good. How in the hell has the shaft moved that much? Especially into the yoke like that? I filed it down some but it was gouged on both sides.