I've been thru this same situation with the 9" swap into mine. After replacing the tailshaft bushing, new U joints,new slip[ yoke, new driveshaft (well really a good used 04 Stang unit) New pinion bearings, changing the pinion angle & swapping from a short pinion yoke to a longer one, I've still got a vibe in the shaft, both on accelleration and decelleration. Anyone got any more ideas ?
Check the pinion angle.9" is bigger...bolting it in the same place as the 8" doesnt mean the pinion angle is correct.You may have to shim it up a bit to correct the angle.
I adjusted the angle independent of the 8" I then shimmed it up more in an effort to fix the vibes. The vibes aren't near as bad as they were at first, but they're still there.
I always thought pinion center-line should be parallel to output shaft center-line. In other words, the angle relationship of the pinion to drive shaft should be equal and opposite to the angle relationship of trans output shaft to drive shaft. Trans mount bars and new style mounts can move the output shaft up and down, likewise rear swaps and perch mods can change pinion angle. Did you try to move the driveshaft 180 deg. to see if that helps?
Badad...Your going to want to adjust the pinion angle...The way it sits right now as per your description...Its wrong...too much positive offset.You want the same amount of negative off set as you have positive at the trans yoke.Betch thats your vibe problem...
