The earlier XJs have a vacuum motor to engage the front axle when put into 4wd. If the vacuum isn't present, or diaphragms are bad in the vacuum motor (on RH side of front axle) it won't engage.

https://www.cherokeeforum.com/f51/my...ana-30-a-6966/

There is a cable actuated kit that can be installed to eliminate the vacuum operation, or there is another, less expensive way to engage it constantly like the later XJs not equpped with the vacuum motor.

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

 

im not quite sure on the front axle i will have to look

so basically with that link, your 4wd is always on, no matter where the shifter is?

 

Because it's an open diff. When you get stuck then the tire that has grip will stop and the tire that don't will spin. Just the way they made em. And does it spin a little or not at all? You said it spins a little earlier.

 

No, the front axle always turns, but isn't engaged by the transfer case unless in 4H or 4L.

 

it spins a little but this is with no resistance on any of the tires, just freely floating in the air

 

Jack up the front and have someone hold one side as you turn the other, if the there is no resistance the you have a problem. If thats the case then check for a busted axle shaft or ground gears.

 

can this be used at highway speed?
if so im so game!

 

i think you're not supposed to use it in 4hi or 4lo in the road it's just for off road, loose surfaces like sand, mud... stick to 2wd in the pavement

 

You can use 4hi on the road if it's slick out unless you have the selc-trac you can use that on any surface.

 

start it up shift it to 4x4 mode under neath look on the pass side back of front axle there will be a round servo connected to the axle with some vacuum line connected to it pull them off and feel if one of them has a slight suction to it if not theres a vacuum issue if there is the diaghpram has issues

 

haha no i meant that wasnt going to harm 2 wheel drive on the highway
but thanks, im trying to talk my dad into this, he isn't very mechanicaly inclined
haha

 

the cable just eliminates the vacuum thats factory when you put the transfer case in 4x4 you have to also pull a cable to lock the front axle in

 

fixing the factory system is a lot cheaper usuallyhttp://www.4x4posi-lok.com/app_jeep.html

 

well im talkin bout doin that free mod
the one thats in the tech section
https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/
has anyone had any trouble with that?

 

That's basically how your 2001 works. It doesn't have the vacuum motor.