'96 Jeep Cherokee 4WD High pulls car to right and has slow disengage with thump

jeep
cherokee

#1

I have a 1996 Jeep Cherokee Classic 4.0L with ~130,000. I recently started pulling a small trailer for wood season (~1/2 cord pine). I have needed to occasionally put it into 4H, and once into 4L, in order to get us some steep dirt hills and to not rip up friends driveways.



Today when I was leaving my friends house I had it in 4H and I used the lever to put back into 2WD. I heard sort of a whirring noise and noticed the car pulled to the right. After about 20 seconds I heard a loud thud (sounded like I ran over something) and the car drove straight and the noise went away (assuming it dropped back in 2WD).



Can anyone help me identify this problem and let me know how serious the fix will be . Winter is coming and I would like to get a grasp on this.



Thanks,

Brian

Bend, OR


#2

If I had to guess (and I guess I kinda do) I would say it’s the vacuum motor that disengages the front axle shaft on the right side from the differential. Crawl under the rig and look at the axle housing on the passenger side, you’ll see some vacuum hoses. Make sure they are intact (not torn or anything) first of all. If you feel so inclined, you might disconnect the little vacuum manifold there and make sure that dirt and mud hasn’t gotten up inside. I’m pretty sure your problem was just the vacuum motor being slow to disengage.


#3

It just sounds like your 4wd was bound up and finally the gears released their hold. Do you have four matched tires in make/model/tread depth? Also when disengaging were you decelerating and driving in a nearly straight line, if you were not 4wd will do this. Its much easier to disengage 4wd on a slippery surface vs on bone dry pavement.


#4

As I thought about it more I remembered that yesterday morning when I tried to pull the 4wd shift lever into 4H it had a difficult time going in. I put it back into 2wd then wiggled the lever and eventually got it to go in. It didn’t seem to have a problem getting out that time.

This problem seemed to happen quite suddenly as opposed to gradually getting worse over time. The first time I noticed it I was on a dirt road, and when I tested it again I was on dry pavement. Both times I was going straight and decelerating. Prior to this problem occurring it would always drop out of 4wd at a stop w/o a problem.

I don’t know if it’s related but I have noticed over the years that if I drive for any significant amount of time in 4L then I get a check engine light for a few hours afterwards and I believe that the oil seemed like it was getting cooked a bit (got much blacker).

Thanks for all your help. Once it warms up a bit over here I will get under it and take a look.

Brian