Just replaced the seal on my rear output on my np231 transfer case and I cannot get the yoke nut down to 150ft-lbs. it just starts to spin after a while. When I first started driving, it was fine, but after a while, I started feeling driveline vibes at higher RPM's while accelerating and at highway speeds...obviously at high RPM's. I have a feeling the yoke nut has loosened since I couldn't get it torqued to the correct spec. I had the transfer case in 2WD when I tightened it. Is there any way to keep the yoke from spinning when I tighten the nut and is this something that could cause driveline vibes? For the record, my pinion angle and u joints are all good before you ask. Those were the first places I looked.
Thanks...that worked. Was able to torque it spec. Unfortunately, the vibes are still there. I'm thinking it's gotta be the hub bearing in the t case allowing some slop in the output shaft. Anyone else experienced this problem?
Does the front yoke have any in/out play to it? I have been having vibes and removing the front driveshaft fixed it. Likewise, all the u joints look and move just fine. If there shouldn't be any play (mine has barely enough to be noticeable, but it is there) what would I have to replace to fix it? The seal? or the whole yoke?
No, I took the front driveshaft out and the vibes were still there. My vibes are pretty bad. At about 50-60 mph there a strong vibration right under my butt almost. Feels like the jeep is about to fall apart
If you feel it in the floor or your seat then it is coming from the rear... feel it in the steering wheel then its the front... Check your ujoints on the rear shaft and/or your rear axle pinion bearing. Also, it cold be an out of balance tire....
If rotating the driveshaft 180 deg doesn't stop the vibes, there are really two possible causes.
1st, the vibes may have damaged a u-joint. Once a cap is trashed, the shaft will vibrate. I think that you might have noticed any stiffness or noise when the driveshaft was pulled to allow you to tighten the output yoke nut.
The other possible cause is the loose nut may have allowed the splines in the yoke to wallow out. You may need a new output yoke. I had to replace mine due to a manufacturing error (the bolt holes were mis-drilled). Tom Woods has replacement yokes for about $75 plus shipping.
My symptoms were just like yours, all due to only 0.035 of an inch off center so it doesn't take much to cause significant vibrations. I had to use a old ball yoke (the part of the driveshaft that bolts to the transfer case yoke,) and a dial micrometer to discover the problem on mine. Once I swapped out for a new output yoke, no vibes!
Hope this helps..
Horse: the original off road rig.
Jeep: just as fun and no stall to muck.
Location: where I wheel: N 45║ 36.663' W 123║ 20.935'
Originally Posted by BlackBetty87
Thanks for the tip MyPantera. IslandTJ...not knocking it, but what would removing the rear driveshaft and rotating the yoke 180 degrees accomplish?
It goes to the effect of balance and reinstalling the shaft exactly the way you removed it. It's a cheap diagnostics check and for some that have reported vibes when replacing u-joints, it was because they didn't reinstall/position the shaft on the original clocked position. Upon turning their shaft 180░ to the original position, the vibes ceased.
May be worth it...
1998 TJ Moss Green Sahara w/ numerous scratches & dents whose playground is on a tropical island that's 33 miles long and 4-12 miles wide, in year-round 82 degree weather