gluestick

Alright folks, here's the problem. When I am simply coasting and not using the accelerator, especially so between 30-50 mph, then I feather or gently pump the accelerator, I can hear a "click" or almost "pop" kind of noise from somewhere up front. It is very brief, but is clearly audible when the gas pedal is tapped shortly and quickly. I watch the tach, and it does not seem to represent a gear change, as the tach stays pretty steady and just slightly moves, as opposed to when you step on it harder and longer and it is shifting gears and the rpms would spike then drop off. Problem happened just occasionally, starting perhaps 2 months ago. Seems to happen more regularly now, and is easily repeatable when I want to do it. I am really sensitive to any odd noises and such now with top/doors off weather finally here. For info, it is a 2008 JKU, AT, 3.73 gears, and a 2.5" lift. I shot this video:

My driveshaft - YouTube

Clearly there is play, and this is almost certainly the source of my noise. The ball joints are out of the equation, they are tight as a drum, I checked them first.

1) Is this a normal amount of play? When I create the noise while driving, it is not exactly from a "normal" driving scenario, feathering the accelerator is not really typical driving, steady and regular pressure does not create this noise. I think I found the noise sort of accidentally, and now, knowing how to duplicate it, make the Jeep make the noise.

2) Is it a problem? As in will it cause my rig to drop the DS while driving at 80 on the highway and put me on the 6:00 news some night and widow my wife and leave my children without a male role model?

3) If it is a problem and is not a normal amount of play, did I create this problem with my lift? 2.5" put on about 6000 miles ago. My gut says no.

4) Is the U-joint the simple an inexpensive fix? Saw this on youtube, sorry for the cross forum post, but this is spot on and looks stupid easy: How to change a jeep jk u- joint - YouTube . Furthermore, is this just a cheap and temporary fix and my lift may have created the need for a new driveshaft? I know when you go 3" and up, this is a must do, but I have not heard of anyone doing a 2.5" BB and toasting their stock DS, especially at such low miles.

Thanks in advance.

gluestick

After further review, U-joint looks tight, play seems to be happening where the DS meets the diff. How much play/noise do you have when you try to hand twist your DS? If out of the range of "normal", what the hell would cause this?

msykes

The backlash is normal. It will increase as the gears wear in more. Looking at my stock gears when I replaced them, they were pretty well worn. Also, consider a real front & rear driveshaft, if you do any off-roading thats more then hardpack or sand; the cv joins on mine blew and left me stuck. I had to winch out.

grumpy1

typically when I have had similar problems, mines usually the rear ds, I know I need to repack the Ujoint bearings with grease. your play doesn't seem to bad yet but if you let it go to long you will need to replace the Ujoint.