Hopefully someone will have a suggestion. I have a slight vibration in the rear of my 2000 XJ. It can be heard when the brake is depressed. As soon as you release the brake and move it disappears.
It is right above the rear differential and I can feel the vibes through the carpet. I've climbed underneath and searched and can find nothing loose or even anything that might be the cause. It's annoying at a stoplight.
Anyone have any ideas?? thanks.

 

Have you checked the rear brakes lately?

 

Thanks for the reply but what do you think could cause the vibration in the center of the axle from the brakes? I did pull the drums when I got the XJ and everything looked good.

 

I have a few theories. Check to make sure your exhaust isn't close to something, it could also be the cat coming apart I know them things rattle if they are bad. Could also be the muffler. If you have a receiver in the hitch it may be vibrating, I've had them do that to me before. Does it just do it when your at a stop light or when you stop in general. Or is it "while" your slowing down to stop?

 

Only when the engine is idling and usually when the brake is depressed. I've checked everything mentioned. I can feel the rattle/vibe through the carpet just behind the back seat in the center. I've checked over and under 3 times. I'm baffled.

 

Kind of a stretch....could be a gas tank coming loose on its mounts and resonating a bit. You said when the brake is depressed, do you mean depressed while decelerating or depressed while idling or both?

 

only when idling

 

Do you still have your rear sway bar in your XJ? Could be a vibe being transmitted through the sway bar and your feeling it where the sway bar attatches to the body/frame right under the rear seat.

 

these rattle/vibes can be very decieving and hard to find...not to ask a stupid question but did you crawl underneath it while its idleing to pinpoint the noise? i know my 96 made several rattles,tailpipe,worn out upper shock bushing and gas tank

 

1. Jeeps are some of the noisiest vehicles around, but they get the job done.
2. If you're only feeling it when idling and stopped, it may just very well be a loose part or some other 'natural' noise.
3. Is your spare tire snug? It could be transmitting vibes through the floor as well. A few minutes with some help from a buddy and you'll find this thing.

 

I'm always underneath it checking stuff. I'll check the trackbar again. The vibe is coming from directly center just behind the rear seat. And i have checked it out while it was running. I can't figure it out. When and if I do I will let ya all know. Don't hesitate to keep throwing suggestions at me though. Thanks.

 

Just behind the seat you said? Possibly a loose jack or other hardware vibrating? Could be the seat itself. Remember, just because you feel it in one place, it could be coming from somewhere slightly different.

 

jeeps vibrate and rattle all over the place. the idea of it being your cat sounds good. have you tried putting it in neutral while idling? with your foot on and off the brake to see what happens. my exhaust rattled against my leaf springs when i first did my lift, made an awful noise, just moved the clamp over and it went away. it's a cat and mouse with these jeeps, you just have to keep troubleshooting to find the problem. i've been at it for quite a while now and its drivin me crazy.

 

Pop your rear seat up it could be that your jack is loose or maybe the wing nut fell off and the bolt is vibrating