put in 8 3/4, now have vibration

If the vibe is getting worse with speed, then you have a issue with the shaft itself or you may not have 2.5 or more in the bushing.

coasting in nuetral rules out the front half of the trans and everything in front of it, which leaves the shaft and rear, and for the rear to make a vibration it'll usually not going to be able to get to speed again.
A bent wheel or even loose wheel can too, but i'd look at the shaft and see exactly what is what, is it a long slip or short slip, is there 2.5 or better in the bushing or is it just short of that.


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