2013 Rubicon 4:10's automatic

I've been doing a ton of research and can not find the issue I have with my new JK. This issue started at 1300 miles and has become louder and you can definitely feel it. I now have just over 2000 miles now. I need to know what to look for in a perfectly stock JK. I'm at a loss and my dealership says it's normal....it's definitely not normal!!! Non of my other JKs ever did this.
Here is what it is doing:

1) vibration oscillates every 1-2 seconds
2) it's harmonic and can be felt in the steering wheel/gas pedal/floorboard
3) it appears after 40mph-54mph
4) if you downshift or get off the gas it goes away
5) It's only when you have light pressure on the gas pedal to hold your speed

Need to know what to look for. I've been under the JK trying to see if something is hitting something it shouldn't. Nothing is rattling or loose.....
I'm at a loss!

 

sounds like a out of balance driveshaft...it could also be a wheel that was machined incorrectly or even a tire that is out of balance...i think i would start off rotating that spare tire around and eliminate a wheel problem first...

 

Sounds like tire balance probblem. Check for missing weights. Those Rubicom BF muds suck to keep balanced. I also had a bent rime right from factory once.

 

I had this same issue with my brand new 2012 when I first bought it. It was a tire that wasnt balanced correctly. Took it to the local tire shop and got it fixed

 

well my fiance has a set of stock rims that I'm gonna switch out with mine....see if it makes a difference.
I just don't think that it has to do with the rims/tires. If I had a bad one I would think this issue would of shown up a lot sooner.....don't you?

 

At 45 MPH a stock tire rotates about 8 times a second. Its a kind of throb, something you'd feel but not hear.

At 45 with 4.10s the drive shafts rotate about 33 times a second. That's like a really low note in music, the kind of vibes you'd get from a good sub. It would make other things vibrate around the Jeep.

If eliminating the tires doesn't clear it up, it would be easy for the dealer to remove one drive shaft at a time to see if one is out of balance.

 

A tire or wheel out of balance would not go away when you let off the gas. It is in the drivetrain somewhere. My guess would be a CV/ U joint in the front driveline. Does it change when going around a curve?

 

I'll have to see when I go out today.....I'll check and see if it does it in a corner.

How have you been? Haven't seen you on to many rides lately....

 

yes it is like a low bass note. All the weights are on the driveshafts.....but could be out of balance.

 

I had an 04 grand Cherokee with the exact same issue it ended up being the torque converter.