Moaning Rear End

jtjones · **Posted:** Fri Jan 05, 2007 4:47 pm

Wondering if someone could shed some light on this sound for me before I dump a load of cash at the dealership (which I do not want to do).

My '02 Liberty makes a moaning noise when I turn corners at fairly low speeds, it's not a constant noise it lasts maybe a second then quiet then the noise again then quiet all the way through the turn. I noticed it a few months ago and had a couple of friends look at it, they suggested that I might change the fluid in my rear diff and put "quieting solution" in it. I know that limited slip diff's require quieting solution but I'm not sure that is my problem. It doesn't make any noise when I'm driving straight and the noise is definately coming from the rear.

Any ideas?

Donkeykong · **Posted:** Fri Jan 05, 2007 6:18 pm

If it's not there when you are driving straight you're probably on the right track looking at the diff, but what do I know.

My mom's older Grand cherokee had a bad wheel bearing which moaned when she turned, but it was there when she was going straight, but you had to listen over the road/engine noise.
-Mark

raceinfan · **Posted:** Fri Jan 05, 2007 6:24 pm

I noticed a moaning from mine yesterday morning mostly going straight haven't heard it on a turn yet but even at a light & just creepin forward you can hear it, do ya think it might be a wheel bearing ?? it's a very low tone moan but you can hear it

sleeve84028 · **Posted:** Fri Jan 05, 2007 7:51 pm

jtjones wrote:

I noticed it a few months ago and had a couple of friends look at it, they suggested that I might change the fluid in my rear diff and put "quieting solution" in it.

Quieting solution is actually called Friction modifier. Friction modifier is added to differentials that are equiped with limited slip style differentials that operate via a clutch pack. This fluid [friction modifier] doesn't really modify the fluid around it, instead this friction modifier softens up the clutch material on the individual clutches that make your LSD operate properly. The softer clutch material grabs better when you need to send power to both tires, and yet as a clutch will still slip in turns. However, with a softer material comes faster wear.... The moan you are hearing is probably due to the lack of fluid or worn out clutch material in the tru-trac rear end. [I assumed you have a trac-lok rear end]

So two possibilites exist for you (that I see)

1) Have the rear end fluid draind and refilled

2) If #1 doesn't correct the problem, you'll need to rebuild the clutch pack or replace the LSD

Donkeykong · **Posted:** Mon Jan 08, 2007 9:54 am

sleeve, is the true track an aftermarker rear end, or would it be on my 06 sport?

I always thought that there was an open diff in my truck.
-Mark

sleeve84028 · **Posted:** Mon Jan 08, 2007 10:35 am

There is an available LSD offered from Jeep (for the liberty) but you would have to select the correct option box to get it... Back when I ordered mine it was the off road package that included the limited slip from the get go.

How many miles on your Liberty? Have you checked the fluid level? - Remove the rubber plug on the back of the pumpkin and stick your finger in. The fluid should be at or near the level of that hole (no more than 1" below.) Low fluid levels in the rear end can also lead to a moaning rear end...

The correct term for the factory LSD is - Trac Loc (sorry if I typed otherwise)

performancechef · **Posted:** Mon Jan 08, 2007 1:16 pm

I'm new to jeeps but this does apply. When i worked at honda, many people neglected to replace the diff fluid regularly, every 15-25k miles depending on the model. At around 30-40k the rear would moan most notably during acceleration from a dead stop while turning. Problem was it needed new fluid. It does not matter wether you have a LSD, Locker or open diff. Replacing the fluid is a no brainer! If you let it go too long, your gona spend big $$$. Think of it like this, you wouldn't keep oil in your engine for 20k miles so don't run diff fluid for 30k+

jcphoto20 · **Joined:** Sun Nov 19, 2006 1:36 am **Posts:** 507

mine was making the same exact noise, i changed my diff fluid to mobil 1 75/140 in the rear and 75/90 in the front. only friction modifier i added was synthetic lucas oil stabilizer. i couldnt be happier.

Moaning Rear End

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