Ever since I had my long arm lift installed I've encountered strange vibrations at around 1500 RPMs. It seems to happen at low cruising speeds between 25-35 mph in fourth gear. If I push on the gas to drop into 3rd gear, upping the RPMs, it seems to stop. I recently switched out the front drive shaft for a coast but it didn't have any affect. I've also retourqued bolts on front end components (track bar, drag link flip, etc), still hasn't gone away. Any ideas as to why the vibes and particularly at low RPMs? It seems strange that this wouldn't worsen at higher speeds or higher RPMs. Other than this, the jeep rides incredibly nice on and off road. The EVO plush coils and bilsteins are awesome combo.

 

have you tried pulling your rear shaft to see if that helps? if so, could be your pinion angle is just a tad off or, needs to be a tad off to help compensate for axle wrapping.

 

good suggestion, i'll have to try pulling the ds when i get a chance and see if that changes anything