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

 

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.

 

^^^^^ 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

 

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

 

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.

 

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

 

thanks for all the help

 

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

 

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.

 

Best I could find in 30 sec.

 

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

 

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

 

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

 

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.

 

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