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Discussion Starter · #1 ·
Help I have no 4 wheel drive on my Jeep! Its a 87' YJ 4.2.....Its been sitting motionless since the start of winter for engine related reasons and I went to test drive it today and it wont go into 4H or 4L....the light on the dash says its working but I know it wasn't cause when in 4L my rear tire was spinning in the snow, but not either of my front ones. Most probable cause is-?


[This message has been edited by 87YJBC (edited February 26, 2002).]
 
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Vaccum shift motor or vaccum lines leading there.

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Discussion Starter · #4 ·
Should the vacuum shift motor be kinda loose? If I grab the part where the vacuum lines plug in its loose and can rotate a bit.....

[This message has been edited by 87YJBC (edited February 26, 2002).]
 

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Discussion Starter · #5 ·
Also if I put it in 4x4 and there is something wrong with the vacuum shift motor, would my front drive shaft turn or not? or are they not connected at all? Sorry, bit of a newbie at 4x4ing tech stuff but I wanna learn!
 

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Originally posted by 87YJBC:
Also if I put it in 4x4 and there is something wrong with the vacuum shift motor, would my front drive shaft turn or not? or are they not connected at all? Sorry, bit of a newbie at 4x4ing tech stuff but I wanna learn!
If you put 'er in 4x4, the front driveshaft should turn, regardless of whether or not the vacuum shift motor engaged.

And yes, the vacuum shift motor can be twisted a little bit.

...lars



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make sure your drive shaft is still there maybe someone else thought they needed it more so than you need it because your not driving it just my .02

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I had the shift fork inside the vacuum actuator housing break off on me once. You should check that the vacuum is correct at the pot, only one side should have vacuum at a time, depending if you are in 2wd or 4wd. If it does, pull the fork housing and check that the fork isn't seized or broken. When you put it back together, make sure you line up the shift fork with the shift collar.
 

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I had that prob before in my xj. I broke 2 shift forks and a new complete unit but none of it worked. Had the vacume lines tested and had vacume when and were I should but still no luck. So I took a coller and put it on the rod that the fork slids on and had my front always engaged. No more problems

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Don't buy a new shift motor whatever you do. If you saw what you are buying for 400$
you'd cry:

If you wanna go mechanical, and it works
great on my comanche, check out my site:

andyf.8k.com
 

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I had the same problem and all it took was some electric tape (just for temp though). I checked the air lines and the green was, which is for 2h was vacuuming but the yellow for 4h and 4l was not working. After disconnecting the lines from the transfer case, I realized that air was flowing fine by blowing in each line with a straw. As I followed the lines, a buddy from www.jeapthrills.com told me to check the lines when it gets close to the battery because the corrosion hits the lines and then the lines crack. Sure enough, just by touching the lines to check them, two more cracked on top of the cracked yellow one. After miticulous electric taping, I was able to salvage the lines and next I know I not only fixed the lines but also my 4 wheel was working like a dream.

Check the line by the battery and look carefully!
Hope this helps


Squintz
 

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Originally posted by 87YJBC:
Help I have no 4 wheel drive on my Jeep! Its a 87' YJ 4.2.....Its been sitting motionless since the start of winter for engine related reasons and I went to test drive it today and it wont go into 4H or 4L....the light on the dash says its working but I know it wasn't cause when in 4L my rear tire was spinning in the snow, but not either of my front ones. Most probable cause is-?


[This message has been edited by 87YJBC (edited February 26, 2002).]
All of your vac lines to the transfer case run down the right side frame rail and up over the trans to the transfer case. I have found on numerous occasions the vac lines broken inside the black plastic harness at the passengers feet. (on the frame rail of course)


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90 YJ, W.W.O.R. in house mechanic
 
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