Transfer case popping like hell - linkage?

89 4.0 XJ, AW4, NP242 w/ new fluid.

I think my transfer case linkage is all screwed up. Out 4 wheelin one night, could only get it back into 2wd after some fierce struggling. The next day, I adjusted the linkage and it worked just fine for a few weeks. Come today, I put it into 4wd Full Time to back up a gravely driveway just for the hell of it, and it starts popping like crazy right under my seat, so it's definitely the t-case. It also drove like it was in 4wd Part Time, trying to pull strangely around corners. So I put it into 2wd and figure I'd diagnose it when I get home.

In 2wd it's fine, but in 4Part/4Full it'll pop like all hell in reverse. So I screw around with the linkage and now when I try to put it into part time, both the Part time and Full Time lights come on. Really weird.

So it's definitely my linkage. It seems like it's jumping in and out of 4PT/4FT and can't decide which, hence the popping.

My question to you guys is, is there a fool-proof way to set up the linkage correctly from scratch? Keeping it in 2wd and messing with the length of the linkage isn't really helping me that much, only making it worse.

Thanks in advance!

According to my 1990 FSM, the transfer case linkage needs to be adjusted with the case in 4 LOW (lever pulled all the way back) with a 1/8" spacer between the lever and the lever shift gate, then hold the lever and spacer to the gate with tape or wire....if you are adusting it in 2wd (lever pushed down forward), the popping would be no surprise....do you have access to a factory service manual? Hope this helps, anyone else have any other pointers I overlooked?

Bret S Gray
1990 XJ Laredo
1992 Comanche (way base, but I am planning to change that)

Yeah I have the FSM and it doesn't say too much. What I do is pull it into 4LOW, loosen the nut on the linkage, and move it until it's sorta neutral? As in, it doesn't go far fowards or backwards to bind? The FSM says move the linkage in 4low until the nut slides freely whatever that means. I'll try this tomorrow and see how it works.

I tried the method you said today but it still pops, Its not engaging into gear all the way. Anyone else?

Disconnect the linkage from the t-case and shift the lever on the side of the case by hand/tools and engage all modes. See if it goes all the way in each mode. If it does, you can keep messing with the linkage, but if it does not, you have internal t-case problems. Watch your knuckles!