Rear diff wine at highway speeds - balljoint?

omniphil · **Posted:** Mon Apr 25, 2016 11:26 am

I picked up a 2006 4x4 V6 2 weeks ago with 107k on it. The only real issue that I haven't been able to fix yet is the whining in the rear diff at speed. I thought it might be tire noise at first, but it goes away if I lift off the throttle. It seems to make the most noise at 70mph, and at 65mph its faint but you can still hear it.

I've been reading around these forums and some have suggested that possibly the boomerang suspension arm above the diff might have a bad balljoint and it's transferring noise inside.

Has anyone had this sort of thing and was the fix to just replace/rebuild the diff?

Thanks!

WWDiesel · **Posted:** Mon Apr 25, 2016 11:48 am

Most likely you got a pinion bearing going bad. Common problem based on noise you describe; faster the speed, higher pitch the noise gets. It will only get worse in time. Will require opening up the rear differential to inspect bearings and ring gear. Do not run to long like this, it could eat up the ring and pinion gears.... Take it to a good automotive or transmission shop and let them put it on a rack and diagnose where noise is coming from.... :roll:

good luck and keep up posted as to what you find.... :wink:

omniphil · **Posted:** Mon Apr 25, 2016 1:01 pm

WWDiesel wrote:

Most likely you got a pinion bearing going bad. Common problem based on noise you describe; faster the speed, higher pitch the noise gets. It will only get worse in time. Will require opening up the rear differential to inspect bearings and ring gear. Do not run to long like this, it could eat up the ring and pinion gears.... Take it to a good automotive or transmission shop and let them put it on a rack and diagnose where noise is coming from.... :roll:

good luck and keep up posted as to what you find.... :wink:

So I assume one could just replace the bearings inside?

WWDiesel · **Posted:** Mon Apr 25, 2016 10:30 pm

omniphil wrote:

WWDiesel wrote:

Most likely you got a pinion bearing going bad. Common problem based on noise you describe; faster the speed, higher pitch the noise gets. It will only get worse in time. Will require opening up the rear differential to inspect bearings and ring gear. Do not run to long like this, it could eat up the ring and pinion gears.... Take it to a good automotive or transmission shop and let them put it on a rack and diagnose where noise is coming from.... :roll:

good luck and keep up posted as to what you find.... :wink:

So I assume one could just replace the bearings inside?

True, bearing replacement is the common repair if you catch it in time before ring and pinion gear is damaged.....

omniphil · **Posted:** Wed Apr 27, 2016 10:05 am

A jeep tech looked at it today, he said it was the pinion bearing as well. They quoted me around $1200. This is just a beater jeep for me (I bought it used) so I don't really want to put that much money into.

I'll try to see if I can find some local mechanic to do the labor cheaper. I think I will buy the parts ahead of time.

For parts I would need a diff rebuild kit with all the bearings and races and then some fluid.
Would I need any other parts?

Are the rebuild kits different by year or do all the 2002's-2007's use the same rear diff?

u2slow · **Joined:** Sun Mar 11, 2012 7:26 pm **Posts:** 160

If you're going to do all the bearings.... you also need axle end (wheel) bearings & seals for the rear... both sides. Its because the tool to adjust pre-load on the carrier bearings goes down the axle tube, and its too big to fit through the bearings.

https://www.youtube.com/watch?v=xlCamOSJEXs

omniphil · **Posted:** Fri Apr 29, 2016 1:34 pm

I have an appointment to have all the bearings replaced on Wednesday. Hopefully that should make it quiet again...

JAFO · **Joined:** Thu Aug 13, 2015 10:35 am **Posts:** 54

What would cause the spider gears to loose a couple teeth? My Liberty went to my local shop b/c leaking pinion seal and when opened up found tooth bits on the magnet.
I would add that I don't drive it hard and change fluids regularly.

WWDiesel · **Posted:** Mon Oct 24, 2016 9:23 am

JAFO wrote:

What would cause the spider gears to loose a couple teeth? My Liberty went to my local shop b/c leaking pinion seal and when opened up found tooth bits on the magnet.
I would add that I don't drive it hard and change fluids regularly.

Normally big tires and abuse! If you bought it new and know it has never been abused, then it could simply be a defective set of spider gears. :roll:

Just replace them and hope it never happens again.... :wink:

bugnout · **Posted:** Mon Oct 24, 2016 9:39 am

Before you have the diff serviced, check the Rear upper control arm ball joint on top of the diff.When this ball joint goes bad it can change the angle the diff sits at and cause whining.

JAFO · **Joined:** Thu Aug 13, 2015 10:35 am **Posts:** 54

New lower updated Moog control arms, new upper control arm. I feel this was an issue before I acquired the CRD last August.

Rear diff wine at highway speeds - balljoint?

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