Hello

I have a 91 jeep cherokee I just bought. The 4wd does not engage. I think that it is a vacuum issue. there are 3 vacuum line on the actuator motor and the one closest to the fork does not have anything connected to it it looks like from the manual it tee's into the vacuum line on the same side of the diafram, is this correct? Thanks


This picture shows the 2 attached, there is one more vacuum connection right behind the one in the left of the engine.

 

Do you have a " Command Trac " or " Select Trac " ?
My Diagram is for a Command-Trac vacuum front axle

 

I honestly dont know what I have. I believe it is command track. How would I tell?

 

look on the back of the drivers sun visor mine has a sticker that says "Select-a-trac" and informs me of the proper useage of each gear on the tc

 

look at your tran.case shifter,
2H - 4H - N - 4L = command trac
2H - 4PT - 4FT - N - 4L = Select trac

 

I have a command track.

 

Look over the diagram and compare your lines. you will also have a dash light that will say "part time" when you are in 4H and 4L. the light is vac. operated also , the switch for the light is on the left fender by the blower motor and below that is where the vac. lines come up from the axle.
here is a write up on this setup > https://www.cherokeeforum.com/f51/mystery-vacuum-disconnect-dana-30-a-6966/

 

a 91 with a vac disco? i thought 91's had non disco fronts.

 

I cant seem to find the T/C Vacuum switch. I have verified and the fork moves freely as well as the sleeve in the axle. I have vacuum to both sides of the motor and it appears to also be working.

When i shift into 4 wheel I DONT get a light on the dash.

In this picture it show the vacuum motor The sensor on the end is cut, would this prevent the 4wd to turn on.

And this picture shows the vacuum hose that is not connected.

 

I just soldered some wire onto the sensor and wired it back in and now part time light comes on. How would I check to make sure that the transfer case is working, I can't tell if it is engaged driving it.

 

my 88 xj is having the exact same issue and ive tried all this as well as throwing it up on a lift and engaging the tcase to verify that it is engaging and im just totally stumped...HELP!!!!!!!

 

pull off the thing on the axle and make sure the fork moves when you put it in 4x4.

 

A great thing to do to these axles is bypass the cad system

Pete made a great write up over on CC
http://www.comancheclub.com/forums/v...hp?f=9&t=18415

My system hasn't failed me since I did this.

 

Yeah i'M bringing this one back from the dead. there is a link in here with Great step by Step Info. and isn't that why we are all here in the first place.

(yeah we come here to joke around too but i can get laughed at and called stupid by my wife, so there.)

 

This^^.

And fWIW, vac discos were on CommandTrac only. SelecTrac didn't have them.