T case troubles?

I have a 99 xj with an re 5.5 and a SYE the truck is manual and has a 4.0
I don't even recal if this is the t case from my 96 or from this truck but it worked fine until a few months ago

It started while towing trailers of wood out of the woods and I would hear a pop sound every so often but ignored it thinkin it was stearing. A few weeks later I was about to drive on a beach and realized I can hardy give any gas withouth a horrible load popping noise!!! POP POP POP POP. and the truck didn't seem to have 4wd or 4 low. If I just let off the clutch and roll it's ok but can't take any pressure at all

The t case seems to engage fine and 2wd is fine so I am lead to believe it has something to do with the chain?

I would like to fix this at the lowest cost and least amount of downtime possible. Does anybody have any idea what I should expect to find? I am hoping worst case I can buy a used t case and hope to use the old SYE? Of course as Long as the chain isn't damaged. Best case a good rebuild kit! Before I start fixing it I was hoping for some insight to what I could expect. i usually remove the case to work on it but maybe leave it on and open it to see for this???

Any input will be a huge help. Thank you

the chains have been known to stretch and the rollers can wear out if the lube is allowed to run low for extended periods.
get a bearing and chain kit and tear into it. you may find the teeth on a gear worn down but that's less common than chain wear.

A new chain should fix it. While you have it open, replace the plastic shift fork tabs.

Seems like I can do the job with the t case still bolted up? Even leave the front shaft om I guess???

you will need to pull the front shaft to replace the chain.

the front output has to come off to get the chain on.


if found it much much easier to just pull the case.

there are only 6 bolts holding it to the trans.

it's easier to do on the bench. Once you get it back together on the bench, bench shift it and make sure it goes into 4wd and hi/lo. Also, be careful with the pump tube, make sure you get it seated when you put it back together.

Assuming I can get away with just replacing the chain and shift fork tabs, does anybody know where I can order just those parts?

And also I wonder if just getting a junkyard t-case ($300) and using my existing SYE may be an easier option. I know mine has black fluid in it and has been through a lot. I also once took the best parts from 2 cases and built this one. Assuming my SYE is in good shape.

if your going to spend that kind of money on another Tcase get one with a wide chain and 6 planetary to rebuild yours with. still buy new shift fork tabs.

I had the same popping sound a few months back. Started occasionally like you said and gradually got worse until it seemed I had no 4wd. It sounded like it was coming from the TCase as well. I took it apart and inspected everything thinking what everyone has said, stretched chain. I replaced it, but that did nothing to solve the problem.

It turns out that in actuality I had broken the teeth on the front axle spider gears. Over time more and more teeth broke and 4wd disintegrated. I think it wouldn't hurt to take a look inside your front axle. A lot easier to take a peek than drop the tcase.

ohioman i actually put a new front end in last week......mine was bent but still popping in 4wd

vahasnowaves... that sounds like a great idea but would need more info to get into that. sounds like your saying to just rebuild mine with those better parts? i was thinking about the wide chain but know nothing about 6 planetary?

google it. im not sure what vehicle would provide you the needed parts. but if your going to go buy a complete Tcase from a yard...

its been done many times.

my money is on broken spider gears or a broken Ring gear.
I am assuming you have already popped both covers to make sure the gears are alright though?

When I blew up MY R&P on my 30(4.88s) it was undriveable past like 1 mph, and even then was absolutely frightening and scary whereas Xjenson broke a few teeth off his rear spiders , didn't know it, and ran the rubicon a few weeks later and went home and when we finally pulled the axle we found broken spiders. Same sort of thing. Loud pop bang occasionally.