93 Wrangler - no 4wd at Transfer Case

[lylewood]

I would certainly welcome some input and advice from some seasoned jeep wrenchers.

I got this 93 Wrangler a couple of months ago, knowing that the 4wd wasn't working, decided I could delve into it at some point.

Looking at things more closely now, here's what I am finding: (With the jeep not running), when the tc is in neutral or 2H, I can easily turn the front drive shaft by hand. If I shift the tc in to 4L or 4H, I can still turn the drive shaft, but there is some resistance (especially in one direction) and it sounds like there is some kind of movement inside the tc.

I removed the shifter boots today so I could look down and see the front drive shaft while slowly driving in my field. When the tc is in 2H the front shaft stays completely motionless, but in 4H or 4L the shaft does turn although not like it's completely engaged in the transfer case, but sort of slipping. (Gear reduction is obviously occurring in 4L). I'm not hearing any noises at all, just not getting much of anything to the front drive shaft. I say "not much of anything" because there is this very slight difference when I put it in 4H or 4L. The front drive shaft seems to want to turn some, and I know it's a difference of what's going on in the transfer case, because the vacuum lines are all loose from the front axle so there's no engaging with the front drive shaft there.

Vacuum doesn’t have anything to do with 4wd engaging within the transfer case, does it?

While I had the shifter boots off, I did the tc linkage adjustment, although I don’t really understand what that particular adjustment accomplishes (the one where you put a 1/8" shim between the shifter and the gate etc).
Probably the next thing I need to do is check the transfer case fluid to see if it's full, although I don't know if it being low on fluid would have anything to do with the symptoms I'm seeing.

Might it seem most likely that the chain in the tc is broken? If so, is it advisable to replace the chain, or swap in another transfer case?

I am reasonably good mechanically, having rebuilt engines and replaced clutches on older vehicles in the past, so I think I could probably attempt to tackle this myself.

Sorry for so many questions, and if I seem to be rambling and not making complete sense. I’m just trying to understand what’s probably going on here and what I should do next.

Thanks for any advice.

- LW

 

[jps4jeep]

No, the vacumn disconnect has nothing to do with the T-case, I am 99% positive that you have a worn shift fork. not hard to replace and not overly complicated to do. you should pull the case out of the jeep (can be done in teh jeep but major PITA, pulling the case will actually save you a lot of time) basically pull the front output yoke off, then sttart to disassemble the back of the case until you can split the case in half. the shift fork kinda looks like a large chicken wish bone. there are two contact pads that can wear over time, if the case was routinely engaged with the vehicle moving at speed, they engage quicker. simply pull it out, take it off it's support shaft and then re-assemble, rtv on all mating surfaces of the case.

If the chain was broken, you would know it, you would hear is slapping arounf the case when driving 2 hi.

 

[lylewood]

Thanks Johnny.

Something else occurred to me very late last night. Is it possible that the yoke is spinning on the front output shaft? I assume that the shaft is splined, which would mean that the splines are stripped. It seems to me that if that is the case, that would explain what I am seeing.

But, that's just a guess, and your 99% certainty about the shift fork is probably more likely.

So would it be the range fork or the mode fork that is the problem? It does shift between low and high range, just no 4wd or at best very slippy output to the front shaft. (Is "slippy" really a word? LOL )

- Lyle

 

[jps4jeep]

you would have to significanly split the yoke to have it spin freely of the out put shaft, significantly enough that you would clearly see it.

 

[lylewood]

Problem is definitely inside the tc. Probably is the mode fork pads. The chain is fine. I could touch it through the oil fill hole, and when the front drive shaft is turned the chain moves. If I engage 4wd and then turn the front shaft, it turns harder, but it does turn. The chain moves, but the rear shaft doesn't move of course, as the jeep is on the ground.

Also, probably a bigger problem is that it was completely out of fluid. When I filled it up, it began dripping below the rear output shaft. Closer examination revealed a hairline crack in the case cover. So who knows how far it has been driven with no fluid and what kind of damage has been done to bearings and gears etc. Probably should swap in another transfer case.