not so good vibrations

[Tacedaddy]

So i swapped an 8.8 in my 1990 cherokee 4x4 np242 with a H&T and all was well till i broke a U-joint wheeling last week.

It was probably the mildest break ever just romping on it a little hard and it broke backing up.

Anyways i had a spare shaft and threw that in it and started geting Vibrations at 26 MPH but they would go away around 35. I just chalked it up to being an out of balance shaft, I replaced the universals in my original shaft and put it back in.

But the vibes are still there 26MPH on the nose, i figured i must have bent the output shaft or something terrible so i pulled the shaft again and put the jeep in drive and watched the output shaft spin and it looks perfectly centered to me.
WTF is going on?

 

[Tacedaddy]

So pulled the rear DS out and drove in FWD to work a few days... NO vibes at all, re-inspected the DS and it looks fine

Im about to just put it back in and drive it, the GF says its like a massage :guitar: :greensmok