84 XJ Vibration help

I just got an 84 XJ for my daughter. Besides that fact that it is ugly as sin, it is not in too bad of shape considering what I paid for it.

When I dorve it home, it would shake violently right before it shifted. At high RMP's is when the vibration occurs.

This is an automatic by the way.

The tranny mount was shot, so I changed it out, and that did not help a ton. (a couple of the crossmember studs are broken loose which is another thing I have no idea how to fix)

Where would I look next to fix the vibration? The u-joints? Motor mounts?

When it does shift, it shifts pretty solid. It just shakes when the RMP's are up.

Any ideas?

There are lots of places to check and look at. What is shakeing the whole jeep or is the Jeep shakeing from an axle or DS shaking? Stick your head out the window and see if either axles are shaking more violently than the Jeep. My track bar was shot and it caused the whole front sxle to wobble and man was it scary.

It is the motor or the tranny. The shake only occurs at high rmp's...right before the shift. Once it shifts, and rpm's drop, the shake goes away until the next shift cyle comes up.

The wobble because of the tie rod is different. I had that too.

Here's what I'd be looking into first:

Motor Mounts

U Joints

Tires (Balance)

I hope it's one of those. Just got my Chief back from the shop today... It too was in for a vibration problem. I had a U joint go bad very slowly and it took my tranny with it. 1275 bucks for new torque converter, two new U joints, tranny rebuild, and new seals for the Xfer case.

Oh yeah... long shot could be a drive shaft out of balance.