When accelerating on freeway at about 60-70 mph, front of jeep shakes a bit. Smooths out after 70 mph. No steering wheel shake or vibration. Tires rotated 4000 miles ago and are in good shape. This only happens when pushing on the gas.

 

 

I had a similar shake at 65 or so and ended up being a tire out of balance. No problems since.

 

Yep, I would guess tire balance also.

I buy tires through discount tire. They have free lifetime balance/rotation so I go in every 3k. I have gone in with no shimmy, and left with a bad shimmy. And I have had them rebalance to fix a shimmy, and had to go back 1 or 2 more times to get the shimmy to go away. So, the moral of that story is : just because you have rotated and/or balanced, does not mean it was done correctly...

 

Not trying to run you off, but this forum is actually for owners of Jeep Wrangler JKs: 2007-2018. Only bring that to your attention since you might get more relevant answers (beyond the likely tire balance) on a more appropriate forum.