hum rumble noise turns out to be pinion angle at -2 degree, trans angle -6 degree

[garvir]

this turned out to be easy fix, raised the trans +8 degrees (3/8" in shims) which gave me +2 degrees trans angle left the pinion at the -2 degree. bob bolles in circle track magazine explains it simply parallel and opposite... noise is gone. that 2 degree gives good bearing rotation, 1 degree would be good, a lot of race guys use 0 degrees, they get enough bearing movement with the car moving up and down. i used the moog super strength ujoint, even though the old ones didn't look bad. also put a loop around drive shaft, just for peace of mind, don't want to see a drive shaft coming thru the floor.



when measuring the angles, car setting at ride level, then make sure u joint is perfectly vertical (turn you angle finder cross car) then measure angle of u joint caps (trans and pinion) along the lenth of the car. i was able to measure off the ujoint caps, which gave me the ujoint angles, these are true angles. the transmission pan is not a true setting, and i could not find anywhere on pinion that was true. Gary