Jonny K's JK

Who doesn't like trying to diagnose a jeep sound issue on an online forum. So here's the story, I'm halfway to grandmas to show off the new baby (about 3000km round trip) I noticed a hum when we left thought it was the new power steering pump but it got worse. Now whenever I accelerate or maintain speed I get a hum/whirring/tire drone from both rear tires. Coasting it seems to go away but decelerating with the brake applied it comes back. I've attached a video to help illustrate my issue. You can hear a slapping sound occasionally too but it appears my front driveshaft is missing half the grease boot. Does the front driveshaft spin when driving in 2WD? I would think it get load from the front diff and the transfer case would be in front neutral. Anyways here is the link to the video hopefully I'm not taking the family home in a tow truck lol. http://youtu.be/82BhMc8IaYw 2008 Jeep Wrangler Unlimited Rubicon no lift factory gears 33" tires with 1.5" spacers.

if you can read this, my Jeep is broken....

kfast24

That sounds wicked. Remove your front d/s won't effect anything just don't put it I 4wd with it off. Drive it around and see if the sound goes away. Boom problem solved. On a serious note if your rubber boot of the drive shaft is busted it won't be long before you need a new one if it isn't the culprit already

Jonny K's JK

Ripped the rest of the boot off and slapping sound didn't go away. It does go away if I put it in 4WD high, not the whirring sound though

if you can read this, my Jeep is broken....

Jonny K's JK

So the slapping sound seems to coming from the transfer case, kinda sounds like a rock in there and only when coasting. Here's a video but it's hard to tell the tcase noise from suspension noise. Right now traveling across Saskatchewan on the way to Manitoba. Saskatchewan roads suck!! The only good part is running over gophers or I'm sure everyone would fall asleep at the wheel! May notice I almost hit an antelope making the video. http://youtu.be/jW3RQA1FSE4 if you can read this, my Jeep is broken....

Jonny K's JK

Thanks kfast24!! With the front driveshaft removed the claking sound is gone. I still have the whirring sound when accelerating or maintaining speed. How would one diagnose if it was the driveshaft or transfer case giving me issues? U joint looks good and shaft telescopes fine

if you can read this, my Jeep is broken....

Jonny K's JK

So I made it home, 2937km!! I lifted the rear end off the ground today and the whole differential vibrates, how does one know if it's the pinion bearing or carrier or is it best to just do both. There is clearly fluid leaking out of the pinion seal, I did change the fluid in the rear end in a town on the way and the fluid was overflowing a bit out of the fill plug when I opened it. Also checked for slop on the front yolk on the transfer case and I'm not sure if it's more than normal. Video links attached any help is appreciated!!
Thanks.

http://youtu.be/aTEfGU8r_0I http://youtu.be/RAjJua2ZSXI if you can read this, my Jeep is broken....

kfast24

Glad you got there in one peace. That still sounds wicked. Maybe someone else has an idea of this if your pinion deal is leaking you should replace. As for the carrier the only way to see if it's good or not is open up the differential and look at it. I don't know or ever heard of a pinion seal causing a whirling sound like you have dude