hey, i have a 1985 jeep cherokee with 2.8l v6. The problem is that the four wheel drive wont work..the transfer case locks when in 4wd hi or lo and unlocks when put back into 2wd...but the diff doesn't lock..there are 3 vacuum hoses going the the vacuum motor on the front axle.the hose that is in the middle has very little sucking power and i know it supposed to have alot of sucking power and i have worked on it for 2 days and its a pain...so please help...thanks

 

sounds like your vacuum line might be leaking or clogged. inspect the line for cracks, cuts, etc. i'm pretty sure you can just buy a few feet of vacuum line for cheap and replace it if it is leaking or clogged.

 

yep, check the vaccum lines. especially the main feed(red line). Between the carb and the distributor. in front of the firewall. also the diaphram in the shift motor might have ruptured. you could take shift motor off, slide axel shaft coupler ring over both shafts, move shift fork over to other side. wont disconnect, front driveline will always spin, but youll have 4x4. youll feel loss of power though with that 2.8V6 with that driveshaft always spinning.

 

the red line has plenty of vacuum running through it...and i have checked all vacumm hoses..would any ground wire cause the problem??

 

i know the yellow vacuum hose lock the diff but where does it get its vacuum from???

 

thanks....sooooo much..

 

do more research on this if you are interested, but i *think* all you need to do is change the disconect side axle shaft and add a block off plate to eliminate that vacuum system.

 

sounds like new t/c

 

i have a 1985 jeep cherokee with a 2.5 four cylinder and the 4 wheel drive shaft is spinning but not locking the tires in. can you please help me figure out where the vacum puncator is so i can maybe fix my problem.

 

4wd has a cable disco. upgrade avail.

 

Here's the free and easy fix if you're interested:
https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/

 

just buy mine it all wrks

 

You guys have either a BROKEN fork or the vacuum motor is not working due to a leak or broken..

Heres a CHEAP fix!

Pull the vac motor off the front axle to reveal the broken shift-fork.. lol

Remove the broken parts and throw them away if you want.

Slide the nifty "collar" over so that it engages the front halves of the axleshaft.

Slap a stainless HOSE-CLAMP on the edge of the splines to hold the collar over.

Reinstall the vacuum doohickey. Plug the lines if they are leaking.

Enjoy your 1987+ version of a front axle.

Fixed for 89 cents.

 

Enjoy your 1987+ version of a front axle.

The CAD axle actually went away in 1991 on NP231 equipped vehicles.

This could be a stuck fork, broken fork, or a vacuum issue.

Like diskman says, get rid of it. Here's a simple way to do it if the fork is good, which is very likely:

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

 

I know I need to change my vacuum line, is it hard to replace?