07 vibration/noise issue

[ArtO]

Hello all. I have a 07 KJ with 105K on it. I'm having an issue that hopefully someone can help me with. When driving at 65-75 mph I get a vibration and thumping noise. The vibration is in in the seat, not the steering wheel. It does not pull when accelerating driving or braking. Goes just as straight as can be. I haven't had it above 75 because I just dont need to go that fast. LOL. The only time it changes is when you slow to below 65, then it goes away.
I've checked everything i know to check, front end, ball joints, the wheel bearings have less than 15k on them.
It drove fine until I rotated the tires, then it started. As i took them off to rotate them I cleaned each one. I doubt the cleaning has any thing to do with it.
Any ideas ??? Is it possible that the tires are just used to spinning a certain way and I just have to wait for them to "wear in" ??
The rear tires stayed on the same side, just moved forward. The front tires went side to side and rearward.
Any help would be greatly appreciated. Thanks in advance

Art

 

[tommudd]

Check rear CV on front driveshaft
Check rear ujoints, they may feel tight to the touch but can be rusted solid
Did you have any vibrations before rotating the tires ( they shouldn't need time to break in)

 

[M38 Bob]

I'd expect U-Joint, front driveshaft CV joint, driveshaft slip joint, etc also. Only real way to tell (other than looseness, or tell tale rust streaks from U-Joint caps) is to take the shaft out and feel for tight spots in U-Joint travel.

Bob

 

[ArtO]

Absolutely no vibrations before the tires were rotated.

 

[twowings]

Sure you didn't knock a wheel weight loose? That being said, I'd take the above offered advice and check for other causes than the tires...it would not be the first time an amazing simultaneously-occuring coincidence of unrelated oddities struck a motor vehicle...

 

[ArtO]

I was wondering about the balance weights. I'm reasonably sure I didnt knock any off but figured i would drop it off at the tire store and have them check them all. Just to be sure. If that doesnt help then I'll be about checking the u joints and such.

 

[Birdman330]

Its not uncommon for wheels to throw weights after they've been hammered on, sometimes techs will not double check a balance after they hammer weights on. Its one thing I always did when running the wheel balance machine, was to spin the tires after hammering on weights to make sure the tires were actually balanced.

 

[megatone]

Could be that you have a worn out strut up front and you put a rear unbalanced tire up there and the spinning motion is causing the tire to 'bounce'.

 

[ArtO]

Tires all re-balanced and new rear shocks installed. It is a lot better now. Occasionally i get a vibration out of the front, but not always at the same speed. I have the new front struts/springs on order. Once they're installed I should be all set.
A friend that lives up the road a ways who eats, lives, breathes Jeep took it for a drive and said it seemed like a wheel oscillation issue. Usually caused by worn/old shocks and poorly balanced tires. I guess I owe him a 12pk now.
Thank you to all for your suggestions.

 

[megatone]

A friend that lives up the road a ways who eats, lives, breathes Jeep took it for a drive and said it seemed like a wheel oscillation issue. Usually caused by worn/old shocks and poorly balanced tires. I guess I owe him a 12pk now.
Thank you to all for your suggestions.

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