4wd won't work!

1988 Jeep Cherokee 4x4-automatic-4.0 I6

okay so... just changed my starter/cable/battery terminals(I'm pretty sure this has no relevance but I decided i'd throw it in there just incase.) anywho...got it fried up after fixing it and went to go pick up the girlfriend. popped the shifter into 4 hi and my indicator light didn't come on..tried to back up and wasn't getting traction..opened the door to look down to find that only the rear wheels were spinning.

so.. my 4wd randomly stopped working. I then attemped to put it into 4 low...and still nothing.. any theroies? or ideas as to what I can do...

also just wanted to say thanks for all the help i got with my starter thead! you guys are awesome and I greatly appreciate all the help ..its great when your a noob like me!

get a posi lok for the front axle

accidentally knock the vacuum connector off the central axle disconnect diaphragm when you changed the starter?

JeepXJ_90 said:

get a posi lok for the front axle

Click to expand...

PM me to get instructions on how to do the posilock on the cheap. Can't post it here.

...but X2 on accidentally knocking off the connector. Before I did my posilock my vac line would fall off at random and I've seen guys driving around the county with their harness hanging down. I always think "I wonder if they know their 4x4 isn't working"

some sort of vac problem with front axle engagement, check the lines going to the shift motor first, then look into replacing the motor or shimming the fork to always engaged.

Instead of the posilock you could

A) Change the 2 piece passenger side axleshaft to the 1 piece non/disconnect D30 shaft and add the correct seal on the passenger side of the carrier

B) Shim the vacuum motor over in the D30 disconnect housing to keep the 2 piece passenger side axleshaft always engaged together

Paradise, why can't you post about doing the posi-lok modification for cheap?

Shift into 4hi or 4lo when the engine is running. shut off engine. chock rear wheels. Jack front axle on the passenger side so tire is off the ground. carefully reach under to front drive shaft. does it spin? no... good... your transfer case is locked. Next go over to the tire that is jacked. does it spin... yes? then its either a vac problem or the shift fork inside the housing is defunct in some way. EDIT: If it is something to do with the shift fork or the vac motor ... White= indicator on the dash
Green= connect
Yellow= disconnect
If the "plug" that goes to the shift motor is worn out just rip it off and use some fuel line ect. as a plug end. also if you have a vac tester. hook it up to the desired line. the motor on this axle works independantly of the engine running. in other words once the vac is engaged to a certain line it will remain that way until another vac is applied to it.

okay. thanks for the ideas guys. I climbed under and had my girlfriend shift it around...the linkage is def working well. now this vaccume line your speaking of..where would I look to see if I bumped it off?? I looked all around and I have no clue what I'm looking for?? pics would be super but a description would be nice as well.
thank you gents!atriot:

def need a possi lock, theres some other otions that i might have done myself

My friend had a 90 YJ with the posilock, still didn't engage all of the time. Tore it out and shimmed over the shift fork with some washers and things I had lying around.

Contemplated removing the cable acutator correctly but we couldn't find the original vacuum housings cover so we just cut it off and stuff.

sean058621 said:

okay. thanks for the ideas guys. I climbed under and had my girlfriend shift it around...the linkage is def working well. now this vaccume line your speaking of..where would I look to see if I bumped it off?? I looked all around and I have no clue what I'm looking for?? pics would be super but a description would be nice as well.
thank you gents!atriot:

Click to expand...

What tcase do you have? If your not sure tell us what options you have. Just 2hi 4hi N and 4lo, or 2hi 4part time 4 full time, N 4lo.

This will determine if you even have vacuum disconnect or not.

If just 2hi 4hi n 4lo you have the 231 tcase and have vacuum disconnect.

If the other, you have 242 tcase and no disconnect.

sean058621 said:

okay. thanks for the ideas guys. I climbed under and had my girlfriend shift it around...the linkage is def working well. now this vaccume line your speaking of..where would I look to see if I bumped it off?? I looked all around and I have no clue what I'm looking for?? pics would be super but a description would be nice as well.
thank you gents!atriot:

Click to expand...

crawl under the Jeep like you are gonna change the starter and look at the front axle. If you have a disco axle, you'll see a housing cast into the right axle tube in line with the upper control arm bushing and mount. Attached to this housing is a round diaphragm that should have 2 vacuum lines attached to it. It is either those lines, or the other end of them that will have loosened.

88xjlover said:

What tcase do you have? If your not sure tell us what options you have. Just 2hi 4hi N and 4lo, or 2hi 4part time 4 full time, N 4lo.

This will determine if you even have vacuum disconnect or not.

If just 2hi 4hi n 4lo you have the 231 tcase and have vacuum disconnect.

If the other, you have 242 tcase and no disconnect.

Click to expand...

I have 2hi, 4 hi, N, and 4 lo...so this means I do have vacuum??

you guys are...THE SH*T!!...got under there and it was the vacuum lines that had been popped off.

shorty thank you for the excellent description I found it right away.

I appreciate all the help my jeepy is on the road an 100% for now!arty: