My first guess is I need to replace my transmission mount, but here's the symptoms for a second opionion.

I took my XJ out yesterday to play in the snow, since we had 15" of fresh stuff at the time. When I'm in 4WD (HI or LO, doesn't matter) and I round a corner or have the wheel turned a bit with the wheels spinning a little to get through the deep stuff, I get what feels like axle hop, but it's coming from the center of the Jeep. This is while driving through deep snow, and I've also noticed it a few months in deep sands.

I'm assuming since I'm turning, the front and rear axles are following different arcs, and I'm getting the locked F and R driveshafts loading up and releasing repeatedly. It obviously gets worse when I induce more wheel spin and better when I ease of the throttle a bit to limit wheelspin. It feels like the driveline is jumping up and down 3-4 times per second under my seat.

Does this sound like a driveshaft issue (U-joints appear to be tight) or trans mount issue?

 

Mine was doing that when the motor mounts were bad. Doesn't hurt to replace the trans and motor mounts.

 

Check TC fluid level? chain may be stretched.

 

Time for some noggin pokin' on your end.

 

I'll have to crawl under there in a couple of days when the snow melts a bit to check it. I do know that I last changed it 13,000 miles ago in April of 2014 and I checked the level about a year ago and it was fine. No leaks at all. Seems to operate quietly otherwise.

I'm assuming a stretched chain would allow slack/slop in the connection between the front and rear axles so the TC would snap back and forth. Is there a good way to check chain tension without pulling the rear of the case off?

The trans mount is likely original, or at least I'll have to assume it is, as I bought the Jeep two years ago. With that in mind, I should probably replace it anyway. Where's a good source for a new mount that's strong? NAPA? Hell, while I'm at it, I should assume the engine mounts are original as well and replace them too. Good source for mounts?

 

Throw some engine and trans mounts at it.

 

Will do. Where's a good place to get quality ones? NAPA?

 

Sure.