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NP231 front output shaft seal wearing out

P

pwa2

NAXJA Forum User
Location
PA
Here's the problem. With 3 inches of lift, the front (dual-cv stock) driveshaft was vibing and wearing out the front output seal of the xfer case. with 5 inches lift now, it's worn out again, even with the front u-joints replaced. I dont understand why this is happening, none of my buddies XJ's wear out this front seal. I can't have my case leaking all the time...

HELP!!!

1995 XJ 4 door, 4.0 Liter, I-6. 5 inches lift (Rubicon Express). trimmed fenders, 33" Goodyear MTR. Rear SYE heavy duty from AA. Rear Woody driveshaft. Stock front friveshaft.
 
Sounds like the bearing is loose, allowing the yoke to wobble, wearing the seal. Also, make sure the surface of the yoke where the seal rides is clean and free of burrs and wear rings.
 
Problem 1: Drive line vibrations. Possible solutions: axle pinion angle is too low, drive shaft bent, drive shaft out of balance, slip yoke worn, u-joints worn, axle pinion bearings loose/worn or TC bearings worn.

First step should be to fix any drive shaft vibrations. Take your drive shaft in and have it checked/balanced and/or rebuilt. Adjust pinion angle if needed.

Can i tighten the bearing?
Click to expand...

No, the bearing can not be tightened. There are 2 bearings on the front output. A ball bearing and a pilot bearing. Both will require the TC case to be opened.

Usually, when a bearing wears down it starts to make some kind of noise, a grinding, rubbing, squeal or gear whine sounds are common. A worn slip yoke can sound like a ticking or kind of like a helicopter at slow speeds.

Hope this helps, and keep us posted.
 
yeh I've taken the xfer case apart when i put the sye on. If I replace the bearings will this keep happening? Is there some reason the lift kit should make the front driveshaft vibrate? I thought dual cv's could handle worse angles than this.

Ok, well I wont get to taking the case apart for a few months, until I get another car as a daily driver...for now I may take the front driveshaft off so the front input shaft doesn't spin. thanks!
 
well i've taken the front driveshaft off. it doesn't seem as if it's missing any balancer weights and the u-joints pivot pretty freely. as taking the xfer case apart is a big job I haven't done this yet...but I dont expect to find the cause of the problem. I mean, I've already replaced the bearings so why else could they be wearing out? I dont understand this.
 
As mentioned earlier, check your pinion angle. Post a pic if you can.
Also while the shaft is out, check for play in the t-case and pinion shafts.
 
the front output shaft was fitted tightly to the t-case...no wobble or excessive play. The pinion angle isn't necessarily relative in this case because the front suspension is a 4-link with coil springs--stock...can't rotate the front axle to change the angle. Besides, I've seen and talked to XJ owners with 8-10 inches of lift with my same t-case and stock front driveshaft with none of these problems...
 
pwa2 said:
the front output shaft was fitted tightly to the t-case...no wobble or excessive play. The pinion angle isn't necessarily relative in this case because the front suspension is a 4-link with coil springs--stock...can't rotate the front axle to change the angle. Besides, I've seen and talked to XJ owners with 8-10 inches of lift with my same t-case and stock front driveshaft with none of these problems...
Click to expand...
Thats why they make adjustable control arms.And you havent seen ANY XJ's at that lift with the stock control arm set-up!
 
Do you still have vibrations? If yes, fix this first.
The leak may be from the yoke itself. You would have to pull it to find out, but check for a deep grove where the seal rides. This may be a good time to upgrade to a u-bolt type yoke. New seal and a new yoke, shouldn't leak for a long time.
 
ok thanks. yeh I'll check that out when i open the case. In reference to the control arms...i have stock uppers and fixed RE lowers...maybe if I switch to longer adjustable uppers i can push the top of the axle forward, keeping the bottom the same, effectively rotating the pinion angle...not a bad idea but something I haven't considered because xj's with the same setup haven't had the problem. but thanks, maybe I'll try that too
 
pwa2 said:
ok thanks. yeh I'll check that out when i open the case. In reference to the control arms...i have stock uppers and fixed RE lowers...maybe if I switch to longer adjustable uppers i can push the top of the axle forward, keeping the bottom the same, effectively rotating the pinion angle...not a bad idea but something I haven't considered because xj's with the same setup haven't had the problem. but thanks, maybe I'll try that too
Click to expand...

The fixed legnth RE arms are from a 3" lift, correct. When you went up to 5" it would change the pinion angle, thus causing your problem.
Adjustable uppers should take care of it, this sounds like the source of your problem to me. If not, it will be!
 
Midnight Krawler said:
This may be a good time to upgrade to a u-bolt type yoke.
Click to expand...
Uhh,its a cv shaft it doesnt use straps or u-bolts!!
 
yeh I don't understand this u-bolt type yoke. What is that and where can i get one?

I will certainly find some used upper control arms. Your right about that, none of these cherokees have stock uppers.
 
Midnight Krawler-

you sure I don't have to take the T-case off and open it to replace the front output seal and bearing?
 
ok thanks. i'll need a long weekend to do this. all the help is very well appreciated.
 
95 XJ steering loose and wobbly

1995 XJ 4 door, 4.0 Liter, I-6. 5 inches lift (Rubicon Express). trimmed fenders, 33" Goodyear MTR. Rear SYE heavy duty from AA. Rear Woody driveshaft. Stock front friveshaft.

My steering is very "loose" feeling and wobbly. It's very difficult to drive at high speeds. I can turn the wheel about 45 degrees without the xj turning, then all of a sudden it turns sharply. I built up the lift kit piece by piece and have added a longer adjustable track bar, but haven't replaced the steering stabilizer or tie rod. Some people tell me that the tie rod ends need to be rebuilt but I can't imagine that little play can affect the steering that much. Any thoughts?
 
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