I'm at my wits end here, need some help!

For about the last week or so now, my Jeep has been making a very strange ticking sound whenever I let off the gas pedal. I can't quite narrow down where it's coming from because it only happens at speeds 20mph or higher, and only when I let off the gas. It doesn't happen under load (IE: accellerating, and such). The sound is a very loud clicking coming from the middle to front of the vehicle, from what I can tell by hanging my head out the window. And when I say loud, I mean really loud. Whatever it is hasn't effected my driving so far. I haven't noticed any unusual vibrations or strange problems with steering, accelleration, braking, etc. Has anyone out there had this same problem? Or can anyone point me in some sort of reasonable direction? I'm almost ready to sell my heap, it's driving me crazy!

1992 XJ, 4.0 I6, NP231, Auto, AW4, 3.5" lift, 32's

u joint? I'd remove the front driveshaft and see what happens.

Is there any kind of locker in the front end?

A couple of suggestions based on experience.
1. All u joints can create decieving sounds and or vibes
2. Front brake guard, whenever you have a chance take it out.
3. rear drum brakes

let us know
pete

Or, front wheel bearings (since you're saying it comes from up front.) A worn wheel bearing can present as a clicking under coast (or acceleration - but you'll usually notice it under coast first, since the engine noise will mask it under acceleration.) Once you hit cruising speed, it goes away - but if you're changing speeds, the extra bearing play allowed by wear will present as a "clicking" noise, and should remain until you get to a cruising speed again. The lower the speed where you notice, the greater the bearing wear (pretty much true with anything.)

5-90

5-90 said:

Or, front wheel bearings (since you're saying it comes from up front.) A worn wheel bearing can present as a clicking under coast (or acceleration - but you'll usually notice it under coast first, since the engine noise will mask it under acceleration.) Once you hit cruising speed, it goes away - but if you're changing speeds, the extra bearing play allowed by wear will present as a "clicking" noise, and should remain until you get to a cruising speed again. The lower the speed where you notice, the greater the bearing wear (pretty much true with anything.)

5-90

Click to expand...

After I went out again tonight, I noticed it more and more under accelleration as well. My next question is, how bad is it to drive with bad bearings? This is my daily driver, and see's many freeway miles. Do I run the risk of something flying off while at cruising speed? Or is it relatively safe (albeit very annoying)?

jeepsrock said:

2. Front brake guard, whenever you have a chance take it out.

Click to expand...

How exactly do I take it out? Can they bend easily, therefore making them rub on something?

You need to put it up on jackstands, remove the front wheels and start looking for play, move some stuff around. The U joints on the end of the axles will make a noise when they start to go. That said the ons on one of our TJ's were in pretty bad shape to where I could move the axle stub around, took about an hour to do both, on a lift type alignment machine and my mechanic buddy walking me thru it...
I also wonder if broken motor mounts might be allowing the fan to hit but I think that would be a more constant sound.

RichP said:

You need to put it up on jackstands, remove the front wheels and start looking for play, move some stuff around. The U joints on the end of the axles will make a noise when they start to go..... I also wonder if broken motor mounts might be allowing the fan to hit but I think that would be a more constant sound.

Click to expand...

I checked the wheels for play a few weeks ago, and there was none whatsoever, but I spose it wouldn't hurt to check again. How many U-joints are there in total on an XJ? At this point I wish something would break, so I would at least know where the noise was coming from. I'm considering taking it in to a driveline shop and saying "Replace all the U-joints you can find".

well, rear driveshaft, front driveshaft, one at the end of each front axle and thats it. Wiggling the wheels don't cut it, the wheel flange where the lugs studs are are held in by bolts and a flange with the bearing in it, the universals are behind that and the do go bad, mostly from rust.

Well I pulled the rear driveshaft and drove around the block in 4hi. The sound is gone. It's at a machine shop right now getting new U-joints put in. Something else that came up when I was poking around was when I pulled the check plug for the rear axle, the gear oil came out all frothy and foamy. Is this bad? It's a Chrysler 8.25 with stock gearing and no lockers.

Sounds like you're getting air into the oil somehow - may be a failing seal (not failed enough to leak oil, but enough to leak air.)

Sounds like you've found the clicking sound - a bench vise will also serve for changing U-joints. Make sure you can get the yoke, a "push" socket (slightly smaller than the cap) and a "catch" socket (slightly larger inside than the U-joint cap) all jammed in there.

The XJ typically has a total of seven U-joints - two on the rear driveshaft, three on the front, and one behind each front wheel. Wheel bearings aren't too bad to replace - the rear ones require the use of a press, but the front "unit" bearings can be done with hand tools. Failed/failing bearings should not cause a yard sale - at least, I've not known them to (but they can cause a wheel to lock up when they fail totally - be warned.)

5-90

The only thing "special" you need when doing the front wheelbearings is a torque wrench that will read 180 Ft lbs of torque. Most only go to 150.