Rear End Noise + Vibration

[skizot722]

I have a 2002 Lincoln LS V8 and am experiencing a "thudding" noise (sounds sort of like a hollow thud) over pretty much any bump I go over in the road. Driving the car down the road I feel a vibration that almost feels like I've got flat spots in several tires. I really doubt that I have any flatspots in the tires because once I've driven around for a while the vibration doesn't really disappear.

I was wondering if anyone had any ideas about what the problem might be before I end up having to take it to the shop. Are there any known suspension problems with the 2002 LS? The car has right around 20,500 miles on it.

[shorod]

Have you inspected all four tires for wear/scallop patterns in the tread, bulging sidewalls, proper inflation, and tight lugnuts?

-Rod

[skizot722]

The wear pattern appears to be even and each tire is currently inflated to 31 psi. What are the recommended torque specifications for the wheels on this vehicle? About 75 ft/lbs? Mine has the 5 spoke chromed steel wheels.

[shorod]

I don't have the manual in front of me, but I'd expect the lugnut torque spec to be somewhere in the 85-105 ft-lbs. If yours are torqued to 75 ft-lbs, I would not expect that to be the cause of your noise and vibration.

-Rod

[skizot722]

Yeah. I set my torque wrench to 90 ft/lbs and each lug nut was already torqued that tight. I've double-checked the spare tire (and tools) and battery in the trunk to make sure none of them might be causing it and they were also snug. Any other ideas on what it might be?

[Joe_theboob]

The noise over bumps may be your front sway bar bushings - although w/ 20k miles I'd be dissappointed if that were the case, but you never know. Try searching this thread for "noise over bumbs" and you'll get allot of info on that issue.

As for the thumping - try and issolate where and the conditions the niose is comming from - front or back? Right side or left? At what speeds? Is it on all road surfaces? When the car is hot or cold or all the time.

Here a few guesses; A bolt or something lodged in a tire. A glob of grease on the inside of a tire rim. Maybe a rear CV joint boot failure...