Symtoms bad U-joints

Hallo.
Can someone tell me the symtoms of a bad or worn Dana 30 axle U-joint?
What did you hear and what did you feel exactly?

Thanks Wim

'92 XJ

A thump...thump...thump/bucking when turning.

If the roller bearings have siezed then the u-joint will be tight. I just did mine and doing parking lot turns it felt like the jeep was always in 4wd. When i removed the axle i couldn't move the end of the axle without a hammer. The bearings were dry and rusty. Over time the roller bearings would crumble and grind up. You might hear a slight grinding sound while turning. Over more time these little bearings turn to dust and fall out, causing the rest of them to fall out. Thats when you can get under the jeep and feel the play in the joint just by trying to move it (shake or twist). I have never owned a xj that didn't need the u-joints replaced or that already had greasable u-joints.

Idiot Wind said:

A thump...thump...thump/bucking when turning.

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Thanks. Is this your own experience? How did the U-joint looks inside?

wim.

sullysxj said:

If the roller bearings have siezed then the u-joint will be tight. I just did mine and doing parking lot turns it felt like the jeep was always in 4wd. When i removed the axle i couldn't move the end of the axle without a hammer. The bearings were dry and rusty. Over time the roller bearings would crumble and grind up. You might hear a slight grinding sound while turning. Over more time these little bearings turn to dust and fall out, causing the rest of them to fall out. Thats when you can get under the jeep and feel the play in the joint just by trying to move it (shake or twist). I have never owned a xj that didn't need the u-joints replaced or that already had greasable u-joints.

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Also Thanks. I let clunk the suspected U-joint clunking and wait till it collaps.haha Or is that dangerous? Did yours clunking?

wim

I heard a whine from the front in 4WD but not in 2WD

wim hoppenbrouwers said:

Thanks. Is this your own experience? How did the U-joint looks inside?

wim.

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yup. I have only replaced 3 of them but they all had the same symptoms. One thumped intermittently while driving straight ahead. The joints themselves on all occasions had completely rusted out needle bearings.

no, mine wasn't clunking. but the bucking while turning or it felt like it was in 4wd on pavement when it was in 2wd. Like i said mine were super tight. I like replacing them whenever i get a newused jeep because i know how neglected ujoints are. no one bothers greasing them if they are even greasable and when they go bad they never get replaced.
I would just replace it if i were you... not too expensive if you do it yourself, plus you can inspect your wheel bearings, brake rotors, brake calipers (make sure they are not siezed), pads (make sure the pads are wearing evenly) I try and replace the 3 shitty 12 point wheel bearing bolts with normal 6 point Grade 8 bolts.

If you look at them and they are bad, a lot of times you will see dry, rusty powder where the caps attach to the cross. Another way to tell is just jack up the wheel and turn it by hand while watching the drive shaft. If the inner part of the axle doesn't move at the same rate you are turning the tire, you will see 'play' in the u-joint.
When you take the joint apart, most of the needle bearings will just be gone; thats the dry, rusty powder you see.

wim hoppenbrouwers said:

Also Thanks. I let clunk the suspected U-joint clunking and wait till it collaps.haha Or is that dangerous? Did yours clunking?

wim

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When mine bind or have excessive play they seem more noticeable while turning, especially in 4X.
Letting them go too long can excessively wear the axle seal, causing it to seep. Inner axle seals are harder than U-joints to replace.
The dry U-joints often have a coating of powdered rust on the cap seals. The really worn U-joints have a lot of play at the cap. Anytime I have the tire off the ground, I jam something long (3/8" long extension) into the axle yoke and turn the tire until it jams, any play *in* and around the U-joint caps is easy to see with a flashlight. Any significant play and I replace them.
Nows the time to get it done, in another few weeks the weather is going to get progressively worse. More water, salt or whatever is going to accelerate wear.

Once again 8Mud has a damn good point. You have to pull out the differential innards to replace the inner axle seals. But again, IIRC, Wim's front axles were already leaking before the trip to France. Sounds likely to get worse quickly. Also I recall questions recently about lubing the front unit bearings.

Alright guys, I have something to do in this weekend before the weather gets worser. We have the same rain in Holland as in Germany. haha
The seals in the diff are very important to stay ok. Thanks for that info. it's a good point.

The front unit bearings are not serviceable. Only the inner bearing you can lube, the other is hidden in the steel. If you brake the unit, you can't repair it in a proper way.
The leak from the seal, was the spill of oil in the tube taking out the axle. So my seals are still ok.
The highway in France is very greasy now, Watch out!

Thanks wim