silverls1z28ofdeath

Ok I've had issue since day one with a vibration since I installed my moser nine inch. And I can't seem to figure out where it is coming from. I've had two different trannys in the car two different drive shafts that have been balanced multiple times and multiple different sets of wheels and tires. The only thing I can figure is there has to be something in the rear end. Any help or ideas cuz it needs to get resolved since it is a pretty hard vibration. Thanks

hiltsy855

iTrader: (35)

Vibration at high speeds? Have you checked your pinion and engine / trans angles? They need to match: Check post #13 here.

high impact

iTrader: (5)

Try adjusting the pinion angle. I had a similar experience after reinstalling my moser 12 bolt and a buddy had it after installing a 9 inch. For many years I used to set up pinion angle to -4 to -6 with car sitting exactly like staged. I learned this tecnique from a couple well known chassis guys over the years. That doesn't work with torque arm f-body suspension and I wouldn't have believed it had I not experienced it first hand. You must measure angle with the driveshaft/pinion angle combined (see the BMR video). I reset my pinion angle from -6 total driveshaft/pinion angle combined to -3 total combined angle and my high speed vibration is gone. My car had harmonics that would drive you nuts within minutes cruising at 60-70 mph. Now it's silky smooth and quiet.

silverls1z28ofdeath

I'm have a adjustable torque arm set to -1.5 and it also had a stock torque arm previously and it vibrated with both.

Bob@BruteSpeed

iTrader: (16)

Have you checked tire/wheel run out with the rear of the car up on jackstands, running and in gear? This would let you know if you have a tire, wheel or axle problem. Since you have swapped tires and wheels if you notice excessive run out, then I would remove the wheel and tires and see if the problem still exist. It's rare but you could have a bad axle. Bob

1 FMF

iTrader: (1)

ring gear & carrier runout, and pinion yoke runout.

http://www.circletrack.com/drivetrai...m/viewall.html