4wd Noises

last time i went wheeling i put in 4wheel drive to get out of a small mud whole and i heard strange new noises. it was the sound of something binding and then releasing with a clunk, followed by a jolt felt through the body. Did it again and i showed my uncle who said it was a bad u-joint. I just got finished replacing two in the front d-shaft (the other one was good, or the best i should say, they all seemed good and besides i only had two u joints) and i just tried it out again and it's doing the same thing. it only happens in 4wd high or low and if i just let the jeep roll under very light throttle it doesn't make the noise but if i give it gas it does it and it also made the same noise when switched from reverse back to 1st. Next to be replaced is my front axle u-joints. i bought the parts tonight but have run out of time. anybody had similar problems. any help would be much appreciated. btw is a 95 with an aw4 and np231.


mike

almost forgot that when turning in 2wd no strange noises or behaviors are noticed whihc is making me nervous ( is the transfer case or diff gone?)


mike

ok first off.. give a lil info on your rig.. year? trany/t-case combo?.. that helps.. your discription is still a lil hard to understand though..
are you shifting into 4WD while on the gas in gear?
is the noise always there in 4wd or just when you first shift??

Sorry about the crappy description it was late and i was getting a bit frustrated. 1995 XJ, 4.0 aw4, np231 no lockers, or limited slips. I shift into 4wd while the tranny is in neutral. I put the tranny into drive, without hitting the gas it rolls forward, i give it a little love and it feels like something binds up, then releases wiht a clunk, not so much a slam but a clunk that sounds like gears of something slipping. If i stay on the gas it will do it the first time and then a few feet or seconds later (it's really inconsistent) it will do it again. I also had one instance where it did it after i switched from reverse to drive while still in 4 wheel drive. It also did it once when i switched from drive to reverse, in both instances i wasn't on the gas. I replaced the u-joints in the driveshaft but that did nothing. I'm going to get the front axle u-joints done monday at school if i can and then go from there.
Again sorry for the unclear description, any help would be awesome.


Mike

A worn front axle u-joint can do that, when it binds, then suddenly releases, so I would put off worrying a little until those joints are done, and see if it solves the problem.

If my school can't do it tomorrow imay have to tear into into myself tomorrow night and hopefully have it done in time. I can't imagine it takine too long but i say that about every project and it always takes a lot longer than i expected. Thanks for all the help guys


Mike

School can't do it for a while but before i tore into tonight i figured i'd check out the u-joints. With the tranny and transfer case in N i jacked up one front wheel at a time and spun them, no binding, at all. I did however notice that the front right wheel has some vertical movement in it where the whole wheel and shafts move inside the axle...bearings? Anywho i figured i'd try to diagnose the problem one more time and if i be real quiet it sound like somehing slipping and my new ideas include the transfer case chain, i think it might somehow be slipping on the gear and then catching again. Any ideas i'm open to anything because i really don't know what i am talking about.


Mike

Just pulled the front d-shaft. Put it in 4wd and in gear........no noises. Has to be front end related. U-joints next.



mike

From your description it sounds like you have a bad unit bearing. The symptoms of the wheel moving and the noise with grabbing are classic.

Sorry for digging up such an old thread, but I'm experiencing the exact same issue. What is a "unit bearing"?

dedmete said:

Sorry for digging up such an old thread, but I'm experiencing the exact same issue. What is a "unit bearing"?

Click to expand...

they hold the rotor/wheel to the axle and allow everything to spin.

sometimes called: "hubs", "bearing", hub bearing", or "hub unit bearing"

I'm having some strange noises with my rig. I recently switched drivelines, and the transfer case and I'm still getting it. It's like a slight grinding noise on acceleration in 4HI only. Then when I put it in 2WD, it doesn't disengage until I come to a stop and put it in reverse. Any ideas?