4 Wheel drive problem

1541 Views 7 Replies 7 Participants Last post by Outkast, Dec 20, 2001

magnet

Discussion Starter · Dec 16, 2001

The 4 wheel drive on my Jeep shifts fine , however when I checked to see if all the tires are rotating only the rear tires spin.
Can anyone help me with this problem. Note it is a 2.5 liter 5 speed manual 1990 Jeep YJ.

[This message has been edited by magnet (edited December 16, 2001).]

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Rob H

· #2 · Dec 16, 2001

Need a little more detail?
Type of Jeep (year / model, (auto / manual), transfer case (np231 / np242)
If you have a YJ or XJ with the front axle vacum operated disconnect check that the vacum lines are still attached. (It's located on the passenger side of the axle.) That's a cheap Fix.

Rob Hogg

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jason-ramsey

· #3 · Dec 17, 2001

You have to narrow it down. Put the jeep into 4lo, then put it in 1st gear and let it start moving. Then jump out and take a look to see if the front drive shaft is turning. If it is turning then you know it is a front end problem. Check the vaccuum lines from the t-case to the front end for leaks. you can do this by plugging the suction end of the vaccuum line on the front end. Note*** Engine must be running and in atleast 4hi.. Second you can pull the shift motor off to see if it slides ok. But best to check preasure with a hand held vaccuum tester. Maybe easier to just replace shift motor providing the driveshaft turns..

Note*** Make sure that the driveshaft is engaging hard not just spinning with chain...

Good luck

Jason

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92yj d44 front& rear.4.09
33 geolanders
mazda 626 seats
2.5 susp lift 3" body
Ramsey pro+ 8000
SOA coming in Jan bye bye body lift hello 8" suspension lift

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Jeepasaurus

· #4 · Dec 17, 2001

Did you lock your hubs? (manual hubs)

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Blue 1981 CJ5 31" tires
*Damnit, anyone see where that door went?"

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MikeCj5

· #5 · Dec 18, 2001

Originally posted by Jeepasaurus:
Did you lock your hubs? (manual hubs)

YJs have atuo locking hubs.

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80 Cj5, 360amc, Swampers, Custom 5in. lift, Off Road only
92 XJ 6" Rubicon, 32s, strictly street

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magnet

Discussion Starter · #6 · Dec 18, 2001

Originally posted by MikeCj5:

Originally posted by Jeepasaurus:
Did you lock your hubs? (manual hubs)

Click to expand...

YJs have atuo locking hubs.

I have auto hubs on the YJ

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lars

· #7 · Dec 18, 2001

This may seem like I'm being pedantic but YJs don't have auto-locking hubs. The hubs are splined to the axle shafts. There is no way to unlock them from the shaft short of disassembling them. Instead, one of the axle shafts is a two-piece affair with a vacuum-actuated coupler that joins them together when the transfer case is shifted into 4wd. When in 2wd, the two half shafts are disengaged on the passenger side. The inside half shaft is then allowed to spin freely which results in no front driveshaft rotation when in 2wd mode.

This is a fairly important point because it means that you can't simply buy a set of manually lockings for a YJ, like you would for some Nissans, Fords, GMs, etc. Simply put, the YJ hub is not designed to allow for any axle shaft disengagement whatsoever at the hub end. You would have to change the entire hub, along with the outer axle shaft in order to install a manually locking hub. And that can be quite pricey, which is why many simply opt to change the entire front axle. It's relatively easy to do the swap on a YJ, although you'd first have to find a suitable candidate axle.

...lars

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19911995409993004:144444.103512.58274

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Outkast

· #8 · Dec 20, 2001

Here's a quick test to see if your 4wd is working. On pavement, put the t-case in 4wd then try to do a U turn. You'll know if your 4wd is workin or not.

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2000 Sahara
4" suspension & 1" body lift, Belly Up, 33" MT/Rs

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