Linkage Adjust or Loose T-Case Chain?

I have a stock 96 XJ, auto, 231. Last winter, when I put it into 4WD on slippery roads, it would kinda grind or slip and the transfer case lever would vibrate when I gave it some gas pulling away from stop signs.

It would feel like 4WD isn't completely engaged. My natural reaction is to put it back in 2WD, and pull it up into 4-HI again, but that doesn't seem to help.

This is something that doesn't happen too often. While driving normally (on slippery roads), there is usually no indication of a problem with 4WD, until I put the drivetrain under load while pulling away from stop signs. I don't know how to recreate the problem for diagnosis / repair, especially since the ground is still dry around here.

The Cherokee has seen no use of 4-LOW, however last winter I did test it in a snow parking lot, and operation in 4-LOW seemed to be normal. I couldn't get the transfer case to slip, but I didn't try very hard either.

Basically, I've already ordered a new transfer case chain, but I'm posting here to get your opinion - I've jumped the gun ordering new parts before.

Is there anything specific I should check before I tear apart the transfer case?

Is it likely that it is just a linkage thing?

Would you concur that it sounds like a loose or stretched chain?

I think you're probably on the right track, at least in terms of looking inside the case, but I'd check the linkage carefully first anyway. If it isn't going all the way in to 4 high, it should be even worse in 4 low. There's more tolerance for poor adjustment in the 4-high position than in the 4-low. The other linkage possibility might be that it is overshooting, and popping into neutral, though. If that happens, you'll lose power to all 4 wheels. I really don't know how far off the adjustment would have to be for this to happen.

When it's in 2-high, the handle should be just about parallel to the floor. If it is noticeably not, you definitely should check the linkage. Assuming you find no damage, excess wear, etc. in the linkage, the adjustment is easy.

Underneath, look for a rod with a collar on it, and a bolt head on the collar. Loosen the bolt. If it's rusty, you might have to work things around to get the collar to slide on the rod. Then use the lever on the transfer case itself to shift it into 4 low. Make sure it's really all the way in. Now put the lever into 4 low, and retighten the bolt.