I took my jeep ('98 XJ,4.5" lift, 32s, auto) out wheeling and then brought it home and parked it, it was fine. Then a week later I started it up and parked it on a retaining wall (about 3' high) with the nose in the air, and blasted it off from top to bottom, and under the hood with a 2 1/2" firehose. It was still fine. Parked it and noticed there was a big dent in my tcase xmember so I removed the xmember and 1" tcase drop and replaced them with a 5spd tcase xmember (I did not reinstall the 1" tcase drop). Now I have a serious vibration when the jeeps idling, it happens in Park, Neutral, OD, Drive, 1-2, and Reverse. Weird thing is when its moving there is NO vibration. My motormounts and trans mount look ok, I did notice that my exhaust mount is closer to the xmember on the 5spd xmember than it was on the auto xmember but it doesnt appear to touch. I am at a total loss as far as knowing what the problem is and I have a fathers day camping and wheeling trip planned so I could use some help.

Thanks, Wade

 

Honestly it sounds like a motor mount or transfer mount. You say they look fine but with the transfer mount sometimes it is hard to tell until you pull the xmember. I would pull it back off and check the mount real good.

 

When I swapped out xmembers I loosened one of the transmission side xmember bolts before I unearthed the 4 nuts on the xmember itself. I tightened the bolt and it seems better, gonna go for a test drive :-)

 

Could be exhaust hitting.. Hop out and look when it's idling and see if you can't find it.

 

I tightened the 18mm Trans mount bolt I loosend (and forgot about) and the vibes are better but still there. Ill check the exhaust hangers next.