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what vacuum system to the rear end? i don't know of any vacuum to the rear axle. you may have limited slip differential which would make both rear wheels spin. there is a vacuum system from the transfer case to the front axle for four wheel drive to engage.

i guess you have me miffed!/wwwthreads_images/icons/smile.gif
maybe i will learn something here./wwwthreads_images/icons/smile.gif
steve

 

I'm guessing that the 4wd was engaged at the time you spun your tires. To check if the front axle is engaged when the transfer case is in 4wd, raise the front passenger tire off the ground and try to spin it by hand with the engine running and the 4wd engaged. If the tire spins by hand, your axle is not engaged. Then check the vacuum lines to the front axle shift motor to see if they are broken or disconnected. Just to be sure you know, there isn't any vacuum to the rear axle. Good Luck and let us know what you find. /wwwthreads_images/icons/smile.gif

PS There is a manual disconnect system on the market called "Rock Lock" by BDS. A cable system, somewhat similar to the old manual choke system, replaces the vacuum shifter. One advantage of it is the ability to have 2wd low range for steering advantage in tight places off road. You just have to remember to pull the cable after you engage the transfer case to shift into 4wd.

 

I guess that I wasn't clear. While in 4 WD, the rear wheels spun while the front wheels didn't move. I'm a newbie to this, but I know that it's 4 WD or 2 WD, but not front WD! Thanks for your posts, I'll check out the lines. Does anyone have experience with the Rock Lock?

 

Ok buddy...
Here is my post from a while ago. I hope it can help you. If you have any specific questions, email me./wwwthreads_images/icons/smile.gif...........
OK, first, the red one coming from your transfer case is the hose for the vacuum source(constant). That will hook up to a hose running behind your air cleaner(not if you have fuel injection) Just look for the small, hard, red line. Take a look and you will probably find the remains or the original red line. Not sure how yours is color coded exactly, but here is the way I set mine up. Take apart the plastic housing around the vacuum harness(don't break it) to see the lines. Connect what seems to match up for now.
1. (blue line) Leave hanging, it has a check valve on it which gets hooked to nothing.
2. (red line) Hooks up to a good constant vacuum source off of the manifold.
3. (green line) goes to the shift motor on the front axle. Horizontal on the shift motor.
4. (black soft vacuum hose) goes to the plug on your firewall by the battery for the 4wd indicator on the dash.
5. (yellow line) goes straight to the shift motor; one of the lines that goes into a two line plug verticle on the shift motor.
6. (black hard line) goes with one of the yellows to the shift motor. Plug located vertically on top.
I hope this helps out a little.
Your best bet is to cough up the $30 that a new vacuum harness costs at the dealer and install that instead of driving yourself insane with broken lines.
Let me know of any more questions or specifics and I will go outside and take some notes on how mine is set up. Because of these lines, I had to drive my YJ in a blizzard in 2wd. Not fun.
This post was from April.
Have fun and good luck

Bryan/wwwthreads_images/icons/crazy.gif
PS. xyj173 will be able to help you also, especially if it ends up being your shift motor on your front axle.

 

I found the problem! It was a simple fix, a bad line by the manifold. Thanks to xjy173 and beee240 for your help. I hope that I can do you guys a favor one day.
Gary