K-SKI

what is a easy way to tell if 4x4 isnt working just went throught yard in 4 low and 4 hi and just spun back tires all over the place how can fix this and what should i check this is my first jeep and i have no clue what to do its a 1990 chrokee sport
thanks in advance

Gee oh Dee

Its prolly the vacuum lines to your front axle.

If you were spinning both rears and your fronts weren't, your not in 4 at all.

fishunterx

^^^^^ Agreed, my jeep has a manual cad bypass on it, took me a little while to get figured out.

Info for full time CAD Bypass here:
https://www.cherokeeforum.com/f51/fr...ss-91-a-38629/

If you don't want to have your axle locked all time like on 91+ you could install this:
http://www.4x4posi-lok.com/app_jeep.html
It replaces the vacuum with a manual cable that you pull to lock the half shaft.

If your confused on what I'm talking about with the Dana 30 front axle. You can find information here:
http://therangerstation.com/tech_library/Dana30.htm

K-SKI

so even if i can feel it go in to 4 with the shifer on the t case it still could be the vac line i think that is what i read

Gee oh Dee

Correct.

You have a 2 piece front axle. If that little box doesn't get the "signal" it won't know to lock the front end into 4.

7newman7

^^^ Correct. I just "fixed" my '91 the other night. Do some searching for "vacuum disconnect".

K-SKI

thanks for all the help

K-SKI

does any one have a diagraham of where all the factory vac lines got for the disconect so i can run new lines

red_dog007

Could see if you just need to adjust the linkage of the 4x4 lever. I had to adjust mine a few days ago. Got stuck in parttime going from Full time to rwd.
Didn't look like I really changed anything when adjusting the linkage but was enough to fix it.

fishunterx

Best I could find in 30 sec.

goblinish15

i had the same issue! my shifter fork had to much play in it. so the vac lines worked but the c clip holding the shifter fork was loose it feel like it is in 4wd. so replace the shifter fork and the diaphram its connected to. its 4 bolts holding that on and u need new diff fluid and whola!!! your 4wd should work again

K-SKI

ok so im giong to atempt to try it to day thanks

if it to much like work and i do the cad bypass instead i have a dumb ? where do i put the gear oil back in the pumpkin i guess
please forgive me this is my first 4x4 ive allways had front wheel drive cars

K-SKI

does any body have a picture they can put on where all this is i found all the lines under the truck and under the hood but where is all the other parts located under the hood

fishunterx

I haven't looked hard enough to know, but from the diagram looks like the actual hoses run to the Transfer Case, and 1 hose runs from the transfer case to the engine for vacuum. Here are some more pic's that I found, google images is a wonderful tool......

This shows the routing under the hood/jeep you can see the hoses running to the transfer case.


This one is a detailed diagram of the actual shift motor running from transfer case to axle.


This one is a more clear color coded basic diagram of the vacuum disconnect.

fishunterx

Read this as well:
http://jeep.zerok.ru/index.php?page=180