My ranger is gas and mine makes the thumping sound as well (very noticeable) think its just a function of this lift, cant be a good thing though probably increase wear on the shocks i hear it all the time on the trails.Installed one on my Polaris EV. Installed easy. Took the front off few days ago because it loads the shocks and when i crossed uneven terrain or a ditch it kept making a loud thump i assume from the shock on the wheel off the ground shooting down. and it squeaks. don't know why the pipe spacers for the struts weren't just machined to fit tight on the top of the strut so it doesn't move around. If you have a gas UTV then the noise probably isn't noticable. Other than that i loved it, got about 3 inches of lift.