Jeep wont engage 4x4

[OG-Unleashed]

so after we went off roading with the guys at gorman, i kinda had too much fun with the jeep

the 4x4 was working till i drove through a small trail which was way too narrow...both sides were trees and bushes. after 3/4ths way up the trail i accidently drove over a tree which was about 12in thick maybe more...and if it wasnt for my bumper it would have been really bad...but the bumper did go in a little.

so i made it back to camp and asked my friend with the winch to try and pull the bumper out a little, which he did. then i noticed the 4x4 wouldnt engage at ALL! i went under neath and i noticed the cable that was going to the differential was disconnected and there was a little water on it, so i reconnected it and checked the fuses, a 25amp fuse was blown so i changed it. it said HD something on it not sure what it was for. but the i checked under the hood and one of the vacume hoses were ripped so i fixed that to and it still wouldnt ingage in 4x4 at all!


We took it into my shop, and my dad and i checked the vacume hoses, and he said the vacume is sucking air, but we still have to check it again because we closed early that day since it was a long day. He said we will take it in again in these next few days...my dad said it might be the little piece on the front differential that the vacume hose connects to...does anyone know the name of that piece and what would it be from????

i let my friend drive it out there and he rear ended my friends blazer, then we fixed it and after that i drove over a tree and only the right end went it but we fixed it

 

[NMRam]

I believe those used a vacuum disconnect on the front axle, but I don't know the part name.

 

[PenguinLTZ]

It's called the Axle Disconnect Servo Motor, the piece on the axle that the hoses hook to.

 

[batman]

thats one of those little things that drive you crazy and i wish i could just crawl up under it and see...i will ask my uncle..he's a jeep man...i'll get his answer as soon as i can!

 

[PenguinLTZ]

On that disconnect motor, if you are sure that you got the vaccuum hose problems fixed, and have good vaccuum, you can take the servo housing off and make sure the fork is free, and the works aren't all gummed up from old gear oil. A failed motor is not out of the question, but it may just be a vaccuum leak like your dad said.

 

[Zembonez]

Is that a Quadratrac Jeep? If not, it has a standard New Process transfer case that doesn't require any vacuum or actuators.

 

[OG-Unleashed]

thats one of those little things that drive you crazy and i wish i could just crawl up under it and see...i will ask my uncle..he's a jeep man...i'll get his answer as soon as i can!

thanks!!!

On that disconnect motor, if you are sure that you got the vaccuum hose problems fixed, and have good vaccuum, you can take the servo housing off and make sure the fork is free, and the works aren't all gummed up from old gear oil. A failed motor is not out of the question, but it may just be a vaccuum leak like your dad said.

yeah my dad said the vacume is working...but we really didnt take a good look at it because he wanted to head home..but do you think the whole front differential took a shit?

Is that a Quadratrac Jeep? If not, it has a standard New Process transfer case that doesn't require any vacuum or actuators.

what do you mean? its a 1991 or 1992 not sure ill check tomorrow

 

[PenguinLTZ]

No, it may just be that servo motor. Crawl under there and see if it's hooked up, if so it may be stuck. You can actually run the engine, and engage/disengage with it removed to see if it works.

Here is a link, it shows a blow up of the axle with disconnect motor, so you can see where it is at.

http://www.cj-jeep.com/cherokee/cherokeefrontaxleparts.htm

 

[OG-Unleashed]

the thing is the servo motor moves back and forth, its not solid in place...but it was doing that before when it engaged in 4x4.....im not sure if its supposed to move like that

 

[PenguinLTZ]

the thing is the servo motor moves back and forth, its not solid in place...but it was doing that before when it engaged in 4x4.....im not sure if its supposed to move like that

It shouldnt be moving. The little servo housing (look again at that pic) is bolted to the axle, and the vaccuum motor is secured into that housing. There is a retaining clip that holds it into place in the housing. If it's loose, you may have ost that clip.