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5point9Limited 11-14-2013 03:03 PM

Bad U-Joint? *Pics* PLEASE HELP! 5.9 ZJ
Hey guys, I have been chasing a vibration that is coming from what seems like the rear of the ZJ. It is way more prominent during acceleration at a range of speeds. I don't feel anything in the steering wheel.
So far I:
-Rebalanced the rear tires
-Had a new hanger welded onto the exhaust because it was loose
-Replaced the transmission mount

Still have the exact same vibes. I did some more searching and it led me to take a closer look at the U-Joints. I see metal exposed in the one section of the U-joint. It looks like it separated a little bit.

Can any of you tell me if you see anything wrong just from the pics?

If it is the U-Joint, where should I get a replacement part?

kensnelling 11-14-2013 03:33 PM

From the pics I can't tell if it's bad, just see the dust shield has moved. Usually with a bad u-joint you will hear a clicking noise. Did you grab the driveshaft and see if there was any play in the joints?


RWC 11-14-2013 04:00 PM

A clicking is more likely to be a front u-joint (an axle shaft u-joint in particular).

You'll get a bad vibration under acceleration with a rear driveshaft u-joint, so I agree that this is the likely culprit. Put the parking brake on and the transmission or t-case in neutral (with the engine off so you don't accidentally drive over yourself) and crawl under there. Grab the driveshaft near the u-joint and try to rotate it and wiggle it back and forth. If there's any play AT ALL, then the u-joint is bad.

Replacing a u-joint is a good learning experience. Go to your local parts store and buy a new u-joint. If you're careful and don't bend the ears, you can replace it with just a hammer, a socket, and a pair of pliers. It's easier to do it with a good vice or a press. Search for a thread with instructions.

Assuming that your screen name reflects your ZJ, when you hit up your local parts store, make sure to specify that you've got a 'Niner. The 5.9L came with a larger rear u-joint than the 5.2L.

5point9Limited 11-14-2013 05:58 PM

Thanks, boys. I did try to move the driveshaft, but it was in park and it didn't really move much. I'll try it in neutral tomorrow. I did do some homework on replacing the part and it definitely seems doable. Thanks so much! I'd like to find a definitive part number for the U-Joint for the 5.9.

5point9Limited 11-15-2013 02:14 PM


zacko-zj 11-15-2013 02:30 PM

U joints are a higher frequency vibration than a wheel vibration since your driveline is turning a lot faster than your wheels. That can help diagnose where it is coming from.

zacko-zj 11-15-2013 02:31 PM

And why do you need a part number? That's what the parts guy is for

RWC 11-15-2013 02:33 PM


Originally Posted by 5point9Limited (Post 17734921)

Did you go wiggle the u-joint with the Jeep in neutral? Based on the fact that you just bumped it without a report, my guess is not. You need to help us to be able to help you.

zacko-zj 11-15-2013 03:07 PM

If in doubt change the u joints. They aren't that expensive

5point9Limited 11-16-2013 02:19 PM

Well, I did the neutral test and it looked real sloppy. Dropped the DS and the thing just fell apart. I think I found my problem. THanks again, boys.

Zacko-ZJ I want part numbers because they are not correct in any of the systems because the 5.9 has a heavy duty DS. I want the correct one. Thanks for your helpful comment.

speedbucket 11-20-2013 10:11 AM

looks like a regular 1310 ujoint went in where the niner takes the larger (1330 iirc) u joint

The time now is 11:32 PM.

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