Horrible Noises, Suggestions?

I know most of us have noises as do I, but this new one is down right horrifying. Here its goes, at 53-55mph it sounds like there is a metal bucket with a couple of nuts getting shaken under my xj. I've checked underneath and nothing is loose, when the noise is occuring and I put the transmission in neutral the noise doesn't dissapear. Also, the noise doen't occur when the engine is reved to the same rpm as it would be running at if traveling at 55mph.

Anyone else have this occur? Any suggestions? Thanks for the help in advance

If I'm reading your post right, it sounds as if you've heard the noise when moving under power and when coasting, but not when you are stationary and just goosing the throttle.

I had a noise that could be described that way about a year or two ago - in my case, the yoke on my rear pumpkin came loose ('92 Laredo with Corp. 8.25). I know you said everything was tight, but I remember trying to twist my rear driveshaft by hand when the yoke was loose, thinking that one of its u-joints had gone. It seemed ok to me, but not being much of a mechanic, I might have missed something.

I couldn't tell from your description whether your noise is continuous or comes and goes. My noise wasn't constant. Of course, I may have caught it soon enough to prevent that. Can you provide any more information on how the problem manifests?

Also, several folks have described a stretched-out transfer case chain as sounding like metallic popcorn, so that might be a possibility as well.

More info would be of great assistance here - can you elaborate on what year your XJ is, as well as mileage?

Either way, this sounds like something that should be addressed immediately, before it strands you somewhere.

HTH,

Rob

The xj is a 96 with 118K. The sound is continuous from 53-55 mph then disapears. I've taken it to multiple shops and they can't figure it out, including the shop that Ray from 'Car Talk' owns. I'm completely puzzled so all the help is much appreciated. How difficult is it to replace the T-case Chain?

I'm afraid that i don't know how hard it is to do the chain, perhaps someone else here can help on that count. Try a little searching here and in the Modified Tech forum. I suspect that it's not too hard, but I can't speak from experience. I'm still on my original chain at 204K and climbing.

Have any of the shops that you have queried included dealers or 4x4 shops?

Rob

one would think yoke would do it all the time especially under aceleration but i could be wrong. T case chain will involve pulling t case and dissassembling from there it is pretty straightforeward. try putting it in 4 wheel and see if it makes any difference/noise at any speed a worn chain should make a noise at any speed in 4 wheel.

I've shyed away from dealers, but am feeling I might have to go to one at this point. I'll try running it in 4wd today.

i been thinking it cant be transfer case if it doest stop in neutral cuz the t case does stop in neutral. i believe this noise is rearend related cuz the rear is still goin when u put it in neutral. i would pull diff cover and see whats inside if anything if not check yoke for lots of play and shake d shaft for u joints

It sounds like a wheel or axle bearing; attempt to isolate the noise front or back.
If it is a bearing the noise will change as you turn the steering wheel.
This is the most probable cause of the your noise.
atriot:

So the noise does not occur in 4wd. I forgot to mention early on that the noise deffinitely comes from the front of the vehicle. At 55mph the only turning that I do is when I change lanes and I haven't noticed taht really helps, but also I'm not turning the wheel that much. So far I've had two people look specifically at the front end/bearings and they both believed that it was tight and not showing signs of wear. I'm starting to think that the triop to the deaalership is inevitable.

I´ve had mufflers, that rattle only under certain RPM and load conditions.
Reminds me of some loose, tin, dust covers, fan shrouds and heat shields, I´ve experienced. That would only act up under certain driving conditions.
Try hitting the brakes a little and the gas at the same time, holding it at the trouble speed. And see if things change, loading the drivetrain and seeing if the sound changes, might indicate a cause.