Strange sound started a week ago...Help?

So the best way to describe this sound is a "whomp, whomp, whomp" that starts slow at about 40 MPH, then gets fast and silences around 50-55 MPH. Then it comes back at 70 MPH. When I let off the gas the sound seems to go away. Drive shaft?? It is not the loudest noise, but on smooth roads you can really hear it. I have taken it to the dealer, they inspected the diffs, drive shaft, greased u-joints and told me all was fine. Tires have been balanced twice (Nitto Terra Grappler 285/65/18). No steering wheel vibrations, and the truck drives straight. More info, I am lifted full OME 885s, dakar springs on the rear, LR UCAs

This has really frustrated me, any input is appreciated.

 

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Sounds like the front end, no real feeling just the sound. I think I am going to rotate the tires to see if that helps

 

Check tire balance first. Typically that's the root to any of those issues like that. If that doesn't fix it, alignment would be the next step.

 

Wheel bearing maybe?

 

Getting the alignment checked today hopefully, truck drives straight and tires have been balanced

 

Can a wheel bearing go bad at 9k miles?

 

Kick on your 4x4 and see if that makes it go away. Drivers side needle bearing. I know thats my problem after i leveled my '12. Except i have vibes in my pedals, so that may not be your problem.

 

It's not normal but anything can happen. I had an alternator die within 200 miles before. It's worth adding to your list of things to check just to be on the safe side.

 

Wheel bearings checked, they are fine.

 

Alignment is spot on:

Toe = Right-0 / Left-0

Camber = Right-0 / Left-0

Caster = Right-2.8 / Left-2.6

Good news is that the LR UCAs are holding the alignment perfect.

 

Did you rotate your tires yet? Do your front tires look like the are cupping? If they are starting to cup, when your tire moves from short lugs to the taller lugs it will make noise.

 

I did rotate the tires about two weeks ago and this was the first time the tires have been rotated. I mentioned this to the tech he did say that it could take a few thousand miles for the tires that have been on the rear their whole life to quiet down/smooth out. Does this sound accurate?

 

No, sounds like an excuse to get you to accept noisy tires.

I once had new tires that were fine until the first rotation, then the car constantly pulled to the right. One of the tires would make the car pull if it was put on the front. The tire dealer said it would get better as the tire wears in. Huh? Tires wear out, they don't wear in...

 

I was thinking the opposite. If you have had them on the front for a while they might begin to wear funny and get noisy. Once you put them to the rear it will take some time for them to smooth out. About the time they regain their roundness, the tires that are now on the front will begin to get funny wear patterns. They usually get wear patterns for a reason though, eg: ball joints, alignment out of spec, tens of thousands of miles with no rotate.
It could be an out of round tire though. I had a bfg km2 that was out of round from the get go. On the rear I never noticed it, on the front it seemed like it would never balance and was noisy. The only reason I found it was after a few trips to the tire shop they suspected something else. The only way to see that it was out of round was to put it on the balance machine, spin it and watch the tire from inline with it, if that makes sense. When it is spinning you will see the out of round section jump a little bit.
Hope you find it.

 

Well, I will give them a few thousand miles and see if it changes. The tires only have around 7k miles on them, and this noise has been the only issue. No steering wheel shake or other issues.

 

I get so frustrated by crap like this. Hope you get it figured out. I would at least put your tires back to where they were before the noise, so you could rule them out.
Good luck!

 

Yeah, it does get frustrating. Thanks for the suggestions.

 

Rotated the tires, still no change. Hoping a few thousand miles will change things..??