1994 ZJ viscous coupler problem? - JeepForum.com

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post #1 of 23 Old 10-10-2013, 11:38 PM Thread Starter
bigcase007
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1994 ZJ viscous coupler problem?

Ok recently purchased a 1994 Grand Cherokee with the V8 with the NP249 transfer case with 100K on it. Runs great aside when turning in parking lots, driveways etc. its the front right side seems to want to hop and sounds like it's the viscous coupler from everything I've read. But looking at the tires three tires are michelin 235/75R15, the front right tire is a 225/75R15 Goodyear with horrible cupping on it. Could the problem be just the tire size difference? Or as I fear the coupler is smoked?

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post #2 of 23 Old 10-11-2013, 02:32 AM
Timo_90xj
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Yes, your problem is the different size tire, and most likely it has burned the VC. With the 249 you MUST have same size tires, and adjust the PSI so that the actual diameter is very close the same between front and rear.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...

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1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
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post #3 of 23 Old 10-11-2013, 08:00 AM Thread Starter
bigcase007
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That's what I figured, it seems to be intermittent but looks like I may be doing the TC swap when I can gather enough funds. Thanks for the input.

-Casey
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post #4 of 23 Old 10-11-2013, 09:32 AM
Timo_90xj
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If the tire pulsing/ hopping bugs you a lot, you can unbolt the front DS until you get the VC replaced and you get same size tires.

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...

http://www.jeepforum.com/forum/f13/d...s-etc-1222317/


1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
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post #5 of 23 Old 10-11-2013, 09:41 AM Thread Starter
bigcase007
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Cool thank you, I think I might try that. Is it correct that I will need to use the E-brake when parked to keep from rolling?
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post #6 of 23 Old 10-11-2013, 09:52 AM
PolkaPower
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Be careful, on the early 93-95 249 cases, removing the front shaft can allow the truck to roll in park. Just make sure you are not on any inclines and you put the e brake on.

96+ it doesn't matter.
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post #7 of 23 Old 10-11-2013, 09:56 AM
Timo_90xj
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Quote:
Originally Posted by bigcase007 View Post
Cool thank you, I think I might try that. Is it correct that I will need to use the E-brake when parked to keep from rolling?
Crap, how did I miss you've got a 1994. I somehow read '97.

Yeah, you cannot run the older '93-'95 models without the front DS (or you can, but it's not the best of ideas). My bad, sorry

1998 Grand Cherokee 5.9 LX daily driver, 1.75" BB, 32" KM2s, HPD30 Eaton e-locker/D44a stock LSD, 4.56 gears, custom- fabbed tube bumpers and tube fenders,...

http://www.jeepforum.com/forum/f13/d...s-etc-1222317/


1990 XJ Limited (4-door), 4.0 I6, AW4, NP242, ***rolled and totalled @ 165k miles***

***Under construction***
1990 XJ (4-door), 4.0 I6, AW4, NP242, PBR 42" tires, Unimog 404 portal axles, 110" WB, full cage + uniframe completely rebuilt, front 3-link + panhard / double triangulated 4-link rear,... ***SOLD***
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post #8 of 23 Old 10-11-2013, 01:00 PM
dnuccio
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and if you take out the front driveshaft on a early (93-95) 249, if the viscous coupler wasnt shot before, it will be after you take the driveshaft out and drive it.

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post #9 of 23 Old 10-11-2013, 02:47 PM
tucsonzj
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Quote:
Originally Posted by Timo_90xj View Post
Crap, how did I miss you've got a 1994. I somehow read '97.

Yeah, you cannot run the older '93-'95 models without the front DS (or you can, but it's not the best of ideas). My bad, sorry
haha if you do, make sure your ebrake works very well. but these axles do not like different size tires. hopefully it didnt damage anything inside the diff.

His:00 TJ "Fiona" stuff/stuff/stuff
95 ZJ 3.5" w/242 swap-Sold
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post #10 of 23 Old 10-11-2013, 03:07 PM Thread Starter
bigcase007
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What would be the first thing I should with very limited funds? Get two new front tires? Wait and save up for a NP231 and swap it? Replace the coupler?

Thanks

-Casey
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post #11 of 23 Old 10-11-2013, 03:59 PM
PolkaPower
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Either replace the coupler or case. A bad coupler will just start wearing out the new tires. Besides, if you replace the coupler you will need 5 new tires all the same. The 93-95 249 is more picky about that. If you have mismatched tires or tires with more tread than the others then it will wear out the VC faster. It's power is split 50/50. Later years like 96+ are like 10/90. Basically RWD until the tires slip.
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post #12 of 23 Old 10-11-2013, 04:13 PM
jeepzj1998
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If you get the 242, be certain you get the rear drive shaft as well. Also, don't forget the bezel that goes on the shifter. Probably wouldn't hurt to get the linkage from the donor too.
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post #13 of 23 Old 10-11-2013, 06:53 PM
tucsonzj
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If you have limited funds, if you can find a 242 at a jy and are handy that will be a 1 expense. You do risk damage to your front diff if you continue on 2 different sized tires. Depending on where you are you can find cheap used tires. Hell I have 4 sitting in my garage I can't find someone to buy.

His:00 TJ "Fiona" stuff/stuff/stuff
95 ZJ 3.5" w/242 swap-Sold
Hers: 15 JK Sahara-3" Teraflex
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post #14 of 23 Old 10-11-2013, 10:47 PM Thread Starter
bigcase007
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Sorry to keep asking questions but I know the people on here are a immeasurable amount of help to a newbie like me.

I can get a NP231 out of a Comanche for $80 it seems like a good deal but what's your thoughts and from what I'm reading it should work? Is that right?

Thanks again everyone for your input.

-Casey
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post #15 of 23 Old 10-12-2013, 06:52 AM
ZJfamilyfun
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Ummmm....im confused. Correct me if im wrong, but only the 96-98 249's have VC's. And the 93-96 have more like a clutch pack. So if you are experiencing wheel hop/bind start with the tire and also check the u-joint/CV-joint on that side.
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