I drove my 91 in snow today and put it in 4 WD high. The front wheels do not turn, so I tried 4 WD low still no front wheel action. The lever seems to go into gear and when in neutral on the Comand Trac lever nothing turns which I would expect. 4WD low feels low but only the rear wheels seem to turn. Is the transfer case shot or any other explanation? Thanks

 

91 could have a front axle disconnect wich is operated by vacuum. It could not. If it does, here is the best fix for it.


https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/

 

thanks very much. How is it supposed to work. Is there a way to fix it so it is factory? If so, does it make sense to do it that way or just modify it. Thanks again. Really appreciate the reply. I see now there is another similar thread for a 92. Mine does have that unit as pictured. Could the vacuum line be off or damaged causing the problems? BTW,the front driveshaft is not missing. That seemed to be a question posed in the other thread.

 

There is no down side of doing the mod, and many benefits. It will not fail you when you need it most and the fuel mileage will be the same. They did away with that crap about mid 1991 because it was more of a liability than an asset.

 

Okay thanks again. I will give it a shot.

 

I bought a perma-lock off Amazon for $44 bucks and haven't had a problem with it at all. This is the best option I belive if your on a budget if not get the whole front axle out of a 1995 yj and put that under the front end.

 

Here's what a CAD looks like.

 

Or just lock it in for free minus the 1/2 hour it takes to do so.

 

Okay I am in process of doing the mod. 4 questions. What was the point of this vacuum system? What oil do I put in, do the 2 wires control the Part Time light on dash and does this mechanism lock both front wheels or only the right side it appears to be connected to.

 

1. To increase fuel economy. Didn't work.
2. 90 weight gear lube.
3. Switch for the "part time light is on the passenger side firewall.
4. Does not "lock" both wheels together as there is a differential in the center.
5. are you done yet?

 

The left front wheel didn't turn either only the rear wheels. If the transfer case is in 4wd shouldn't the left front wheel turn even if the right front isn't locked? Not done yet, would be but I broke the circlip that I was being carefull not to lose. Do you think dealer would have or any parts store.

 

Charlie, you're just gonna have to trust us on this. I don't think you have a grasp on how differentials work. That's okay. Do the mod and be ready for the bad weather.

 

Not sure about replacement parts, though likely they are scarce.

And no, because your differential sends power to the wheel with the least traction. If your 4wd is engaged, but the vac disco is disengaged, the front diff will be sending power to the inner axle shaft on the passenger side, and because the vacuum disconnect failed to connect the inner axle shaft to the outer shaft (which is connected to the wheel) it is just a free-spinning unit off the pass. side differential.

Edit: Good call Cruiser.

 

Good explanation on your part. Time for Charlie to get this done and we'll have class later.

 

Thanks for the excellent explanation. As soon as I find a replacement circlip it will be done. Thanks again for everyone's help. I am looking forward to that class.