Shake at 30 mph

[dhoey1212]

Good afternoon guys and gals,
I am trying to track down an issue on my girlfriends 2010 Sahara Unlimited 4 Door. There is this shake or wobble at about 25-35 mph under acceleration. Take the foot of the gas and it goes away, accelerate through it hard and it goes away. Tires have been rotated and checked, got an alight meant recent and the issue persists. Thinking either something with the trans, maybe u-joints on the driveline, or possibly something with the steering rack although it happens regardless of wheel position. Anyone have a similar problem or find a fix for this?

 

[tJKrider]

You can try a different trans gear at the same vehicle speed to rule that out, assuming the issue follows vehicle speed...

Could be driveshaft balance or a u-joint. Your comment about lifting off the gas, however, makes me lean towards either a driveshaft u-joint or pinion bearing. Those tend to respond to the loading/un-loading of the driveline.

I've also had rear axle bearings (on a different vehicle) going bad that would hum and vibrate at a certain speed. Higher or lower and they were silent. That was independent of accel or decel, though, just hitting the right speed...