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I have had it with this ZJ... PICS of damage.


Automan2164
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Anyone know an easy way to turn a NP249 into a 2WD with some redneck engineering? I just had a 3 hour drive home courtesy of the cursed jeep.

 

My story:

 

GF and I were going to the WI state fair, about 80-90 miles away from where we are, mostly 65 MPH highway. About 30 minutes in, we started to notice this real odd smell. We just kind of laughed it off as being the truck infront of us, and kept going. :roll: Once we were about 10 miles from the destination, I noticed the ZJ was smoking. I pulled over, to find one crispy fritter of a D30, all the paint was baked off of it, and smoking like all getout. :headpop: I found the heaven sent wally world, picked up 6 Q's of 140, a 3/8's ratchet, and a fire extinguisher(Thats sucker was getting hot). I hopped a curb to fill it up, and got the plug out. I found nothing but smoke and shavings, and the case was so hot, putting fluid in, was sending it out just as fast out the pinion seal, like running water. :( Not being a glass if half empty person, we were close enough to the fair, and we went. I mean we were there, stranded or not. :dunno: After imbibing some frosty brews image_209027.gif , and fufilling my inner glutton :yes: , we got ready to go. I crawled under, topped off the now cool axle, and we headed out. With 90 miles to go, and a "its already FUBAR'd" attitude, we embarked, taking every country road, back stretch, and truckstop parking lot to quench the axle at 35 MPH at a time. We made it home, but not without some luck. SO I am asking for advice here. I need to get rid of this AWD. I think its my biggest problem here. I just did the axle bearings front and rear 3 weeks ago, and have driven just as far with no problems. I am at the end of my darn rope with this. I really don't even know what I am asking for here, but I guess I just needed a place to rant, soapbox.gif vent, and possibly ask my fellow IL/WI fellas, if anyone has a D30 sitting around. And/or a 231 that will bolt up to the ZJ 42Re.

 

Pics of when the 140 was coming out like water, the spot I left, and yes, that Diff cover used to have paint on it. It spent an hour or two baking at 70 MPH.

 

But I really think its about time I dump this whole son-of-a and get something without the phenominal NP249. :fs1:

Rob L.

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I'm not sure what your problem is with the 249 transfer case. It was your Dana 30 that failed, not the transfer case. In fact, aside from the viscous coupler in the 249 that wears out (actually, the permanent fluid in it breaks down) it's a great transfer case. I know people who have been driving on the fried Viscous Coupler for years with no trouble aside from the wheels chirping at full lock anyways. You can swap a 242 in if you like, most 4.0 ZJ's have a 242. But the full time 249 is a better design than the full time option on the 242 (the 242 acts like an open differential, whereas the 249 acts as a limited slip).

 

I personally like the Quadra-Trac Tcases (249,247) but, it's personal preference I guess. I know guys who wheel with a 249, and 247 with no problems.

 

You may want to consider a new front axle though. :D

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I agree with WR.

 

As far as doing anything with the D30 that's under there.. forget it, its toast. You likely spun the carrier bearings, at the very least all bearings/races are gonzo. that super heated case was never intended to withstand that and cannot be relied upon ever again. Go get a new one and swap it in call it good till you can find a 231 for cheap. JMHO

 

CW

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I've never seen a fried D30 before this! I guess I should "never say never"...

 

Best of luck with finding out what the problem is and getting it taken care of. If I can help in anyway let me know - i.e. pick up an axle you find on CL up here in Madison or something for ya...

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Thanks Brent. CW, yeah, I knew as soon as I looked under the jeep and found the source of the bbq, that'd I'd be looking for the new axle. 8)

 

I think I know what happened though. I have been fighting this driveline vibe for awhile now, and haven't been able to put my finger on what it is. The front d/s was bad, so that got replaced. The vibe was still around, although minimal, and not near as bad. Only showed up around 60 MPH +. I have balanced all the tires, and recently did both front and rear axle bearing sets. The unit bearings seem good, so they stayed on board. But yesterday I was in a little hurry, and hit cruise at 70 MPH, where the vibe comes out. When looking at the axle, it looks like it wallowed out the pinion seal, and then the oil flinger proceeded to throw all of the axles life blood out along the highway, and turn it into toast...

 

Maybe my pinion shaft was bad? Who knows. Hopefully with a new axle, the driveline woes will have gone away.

 

Either that, or I was looking at trading it for an '88 YJ, 4.2L, 5 speed. Its a base model with no PS, but its mint, and nearly rust free. They want $3,900 and the ZJ is worth about that, and also exceptionally clean. I guess we will see what happens.

 

EDIT: For those familiar with the 249 and a fried clutch, is it possible for me to just remove the front shaft and turn it into 2wd for the time being?

 

Rob L. :(

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There were about 7 or 8 ZJs are LKQ Auto parts in Rockford last time I was there. They are pretty cheap.. and you pull your own. I have a 23 spline NP-231 sitting in my parts pile. It came out of a wreck I bought. I had planned to open it up and take a look at the inside and use it for something down the road. But if you need it...

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Well tomorrow is the day. I am pulling it into the shop, and pulling the cover. :brows:

 

I nursed it to and from work today, and put some of this super-gooey gear lube (called gear-up, by certified labs) in hope if would stop any more damage. The guys I work with in the shop used to race in the local circuits, and seem to be pretty sure that with the small howl its making, with no grumbles, the axle assy might still be save-able. :nuts: They have seen some diffs take a beating. Upon a quick visual inspection, it looks like I might have had a pinion seal failure, and thats what caused the loss of fluid. :fs1:

 

All bets are off, I find out tomorrow. Wish me luck! :D

Rob L.

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Upon a quick visual inspection, it looks like I might have had a pinion seal failure, and thats what caused the loss of fluid.

That's usually what causes a diff to pee the juice out around the pinion. What did you think the problem was?

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Short of a housing failure or shearing the pinion off... The pinion seal failing would be responsible for the leak.

 

If the bearing races did not spin, the housing is probably fine. If they did spin, it depends how bad. As terrible as it is, providing the bearing race seating area is only .001 to .002 over-sized, the bearing races can be retained using retaining compound (green locktite, I think is the colour). The actual tolerances on the machined ares as far as relation to each other is actually fairly loose, so even if everything winds up slightly misaligned, the gear setup will still be valid if done properly. Probably. I'd rather throw the housing out at that point, but it's all junk anyways.

 

Beyond that the gears, bearings, races, and most probably the carrier will all be junk. Also, the axle splines should be looked at for the sake of it.

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Finally got the chance to get underneath it. Looks like the carrier and such would still be save-able, but with a local junkyard charging $85 an axle, it'd be cheaper to just replace the axle. I Just replaced the pinion seal to keep it on the road, and allow some time to search. It looks like there were no-external causes that did this... I didn't see any obvious mechanical failures... the pattern is off, but I am assuming due to the lack of fluid/wear there of. So I am inclined to think the only reason this happened was that the pinion seal failed, and set it on a course for self-destruct. (Eagle: I knew a pinion seal will make the fluid piss out, I just meant that I think the pinion is the SOURCE of what happened.) Did my research(thanks for the link dunl), and I think I'll keep the NP249 for the time being... Also looked around nagca.com... Contemplating looking for a 98 5.9L ZJ to replace mine :brows: . IF the price is right. Its drive-able the way it is right now, just a bit noisy :ack: . The front r and p are pretty checked and scored up, bearings seem suprisingly fine. I also decided to check the pattern on the rear, since I was under it, and removing the front cover anyway. Rear pattern looked ok.

 

I took some pics, tell me what y'all think. :yes:

 

 

Front Damage:

 

Front tooth pattern, in current damaged state:

 

Rear Tooth pattern:

 

Rob L.

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HP dana 30 FTW! :D

 

I'm either in the market for axles, or a 4x4 4.7L Manual Dakota/Ram or a 5.9 ZJ...

 

Any axle I put in I want to keep the CV's. I have heard if you put the u-jointers on the np249 you'll feel 'em everytime you turn... :ack:

 

Rob L.

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So buy yourself a cheap XJ, steal the parts you need and part out the rest. You guys should be pretty good at it by now. :brows:

 

whowey was already trying to get me to buy a whole ZJ for what I needed, and said, he be interested in the seats... I need another vehicle like I need another hole in my head. :(

 

Rob L.

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