Rattle I can't find/isolate and fix... need suggestions

Ok... on my '96 XJ, 4.0 Auto... I've had a rattle type of noise I can't isolate that sounds like it's coming f/around the drivers side/firewall/tire area... but that could be deceiving.

Let me describe. My XJ starts and drives just perfect... nothing wrong at all... best I can tell. I've also got 244K miles on the odometer. I started noticing this about 2-3 months ago and it's gotten a very slightly worse w/time. I only notice the sound when I'm driving and come to a stop, while sitting at a stop, transmission in D... I hear what sounds like a rattle and sometimes almost sounds like a whistle... then when I let off the brake and start driving the sound goes away.

I thought it may be my transmission making noise but after changing fluids last weekend nothing changed. The old fluid was in good condition and the tranny shifts fine.

Oil pressure is good. It's possible I have an exhaust leak (replaced my busted OE header w/a good one a couple years back and I don't notice any cracks) Have MORE motor mounts.

The hard part is trying to diagnose the cause of the noise. Anyone every have anything similar and figure out what it was? Any suggestions are appreciated.

shot in the dark really... how old is the cat? try kicking it and seeing if you can get it to rattle.

VAhasnoWAVES said:

shot in the dark really... how old is the cat? try kicking it and seeing if you can get it to rattle.

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Not sure how old my Cat is... I've had the XJ since ~ 125K miles... and never had to replace it. However I have replaced the Muffler and tailpipe section.

Thanks for the suggestion.

The next time it does it, pull back slightly on your t-case lever and see if that stops the noise.

My '00 w/ 173K does the same exact thing. Had another '00 that did it too, but with much fewer miles. My issue is a bushing in the t-case shifter linkage, but I haven't crawled under there yet to figure out which one. I've been living with it for a few years now.

Redsnake said:

I only notice the sound when I'm driving and come to a stop, while sitting at a stop, transmission in D... I hear what sounds like a rattle and sometimes almost sounds like a whistle... then when I let off the brake and start driving the sound goes away.

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Have you tried having a friend sit in the Jeep, foot on the brake, with it idling in Drive, while you crawl under and see where its coming from.
A 3' piece of heater hose makes a good stethoscope.

I have not pulled on the transfer case shift lever.... will give that a try. If that's it, then that solves some anxiety I have... I can fix the bushing later so long as it won't cause a catastrophic failure.

I have not had a friend do as mentioned above... but I can get my wife to do it. I know she loves me and I'm not insured enough to have her let her foot "slip" off the brake... ha.

lazyxj said:

I would use BIG chocks, on rear wheels, if I my wife helped, just to prevent any 'accidents'.
I can hear her say "I'm going to miss him hanging out in the garage all the time".

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Looks like i'll have to give this a try. I tried pushing and pulling and twisting my Transfer Case shift lever yesterday and this AM when the sound started (while in Drive w/my foot on the brake sitting at a light) and the sound didn't change at all or go away. Hopefully it's something as simple as my Cat Converter needing to be changed.

I'm not sure if this will help but I had a rattle that turned out to be the transmission inspection plate bolt hitting(the driver side Big bolt at the very bottom of the bell housing) the exhaust. It is something to check at least, I could see scratches where the bolt was hitting the pipe or just remove it and listen.

Maybe in D you're getting some flex in the mounts that allow it to make contact.

Big Rubber Hammer sometimes helps to find rattles.

Good Luck,
Orange

I have a 92 and I have the same kind of rattle going on, the lady I bought it from said it was something to do with the exhaust. I've gone over all parts (including the cat) of the exhaust and it's solid. I think I felt some "vibration" coming from the front of the oil pan...but that could be transferring from from somewhere else.

Did you ever figure out what the issue was?

So turns out (found it in another thread) it was the 4 bolts that hold the the flex plate(?) to the torque converter were loose. Torqued em down...no more rattle.

Here is the thread I found the info on.
http://www.naxja.org/forum/showthread.php?t=1041301