My 15 JKUR recently started making a chugga chugga noise in the drivetrain. This has been a bitch to track down. Inspecting, I found the front DS seal finally gave way after 41k miles. I pulled it off to troubleshoot and will replace. Noise is still there. The rear DS seal is still intact, so I suspected the rear wheel bearings after feeling movement on one side. Replaced the stocks with new, pressed 10 factory axle shafts. Been meaning to upgrade those for awhile. Noise is still there. Checked for movement on the pinion in case the bearings failed. Zero movements. Opened the diff, all looks well.

So now it's down to the rear DS. The noise is only evident during deceleration around 17 mph. Put the trans into N, still there. Present on braking, and e-braking. Put the transfer case into N AND IT STOPS.

This exercise is starting to get expensive. Pulled out the gopro and made the following video.

Please share your thoughts on what this may be. I'm suspecting the DS, but I can't track the damn noise down.

 

That's a good video of the complaint Sadly, I don't have a "It's this!" answer for you. But, perhaps a couple troubleshooting ideas:

1. Pick up a mechanic's stethoscope (five dollars on up) and poke around to isolate the noise. Obviously that's not good if it's a rotating part you must listen to.

2. Disconnect the rear driveshaft and run that test again. If it does it with the DS disconnected, then you've isolated it to something before that. If it doesn't do it, then that doesn't necessarily mean the problem is in the DS or beyond because it may also be related to the load of turning the wheels.

 

Place the rear of the jeep on jack stands. Remove the rear tires and chalk the front tires. Drop the rear DS. Put it in gear and run to 20mph... if you hear the sound, then it would be in the transfer case.. if not, then the driveshaft of the differential..

 

Thanks for the reply guys, I've run it on jacks and could not duplicate the sound. The only thing I did hear (while on stands) was something that sounds like a marble drop where the CV meets the TC. I'm leaning towards DS but the boot hasn't failed yet. Every instance I've seen of CV failure comes with the boot being ripped and grease splattered.

 

That is indeed an odd noise. The rear DS boots on the 4dr just don't fail the same as on the front DS (the angles are much more forgiving). Since both ends of the rear DS have CV joints, you can flip the orientation of that around.....moving the current TC side down to the axle. It's free to try, and is actually a better way to mount it anyhow as it moves the slip boot further from the evap skid. If the noise moves to the other end, seems like it would be that CV joint. if the noise stays at the TC......seems like a bigger issue.

 

Wow! Thanks! Didn't know they could be flipped! I did notice in the video I posted that it seemed louder in the back. Drained the TC fluid tonight and stuck a scope in the top hole. Nothing interesting in there with limited view. I'm convinced it's the DS at this point. Will report back. Going to order new shafts on monday, convinced at this point it's DS related. Cheers.