Been there done it!

At least you know that these items have been checked and are ok, should be really strange if a spot weld is playing up and causes to grind the rear axle and only after a longer trip.
It looks that they did not have a clue and just checked everything just in case, this is a good thing in a way but does not help you/us any further.
.
I think it is the clutch plates in the LSD that keep sticking when the rear diff oil gets warm after driving for a while, seems that the oil looses its lube abillity a bit and even adding a friction modifier (Mopar) does not help all the time.
I don't know it is because the oil is not up to scratch or that the LSD clutch plates overheat the oil to such extend that it looses its lube-ability.

When I mentioned the grinding to a mechanic once his immediate reply was "have they added friction modifier to the rear axle yet"

I'm convinced it is the LSD.

_________________
The most repeated sentence I heard from my dealer was "I'm sorry YOU are not happy with our service" so it was still my fault.

I have been hearing 3-4 gentle "thumps" at some of my accels from stops. It just started happening at 16,000 miles 4 days ago. Not at every stop/accel. And more at uphill starts-offs.

I thought it is the rearend LSD and it did start after a long ride.

Funny thing is I've been babying my 2005 Liberty since I bought it new...It has not a fun ride. I hope to get this worked out before too long. Maybe I need to do more wheeling to loosen things a bit.

Are there any Amsoil products for our LSDs?

Chris

_________________
2005 Black Renegade 4x4
-- Looking for some ups! --
28D, Tow Pkg, Fully Skidded, Yummy Leather, Mopar Bug Shield, WeatherFlectors, 5x 255/70R16 Bridgestone Dueler Revo, Husky lined, and a brand new eTool. 2005 EVIC Install Write-Up Coming Soon! Currently (6/07) @ 16,400 miles! (3/07-14,100 miles)
http://www.cardomain.com/ride/2175805

the only difference is that my jeep does it right at start up... it doesn't have to be running long at all. i'm really not sure, but he also guaranteed if anything does happen and my warranty is up, they'll honor it. i have this in writing, so i'm breathing easy, although i don't want to wait until it happens. then again, looks like i have no choice from here.

LSD side note.

I did sometimes get some grinding/binding of a thump from the rear axle about a year ago. It would do this when I would back up out of the drive or a parking space. Dealer changed the fluid and added limited slip additive and the noises I'd get went away and still haven't returned.

The reason I bring this up is because I would think that if this was a fluid issue I'd also be having these noises when backing up again.

I've also done some more observations on my current grinding. It does seem more likely to occur after a long drive. I also know that it would do it more often when I was hauling the camper around a few weekends ago.

_________________
'02 KJ Limited 4x4, trac-loc, factory skids, self installed rear hitch, trailer breaks, & trans-cooler, custom crossrails/canoe rack.

When backing up the clutch plates in the LSD could still be dry and lock up, a friction modiier should always be added to a rear axle with LSD and this helps to keep the plates more slippery.

When hauling heavy trailers it is better to use 75W-140 synthetic as the standard lube will not cope..

For normal use I think a 75W- 90 Synthetic will help as it keeps the rear axle cooler and lubes better (within 1 second from start instead of a Minute or so).

I'm in the process of changing from the standard dealer stuff by Mopar and filling it with 100% synthetic, I hope this will solve my grinding issues for once and for all.

_________________
The most repeated sentence I heard from my dealer was "I'm sorry YOU are not happy with our service" so it was still my fault.

After coming back and reading this topic, it is very similar to what I have been feeling, rather than hearing it. I always have the radio on, so I cannot hear anything. When I stop at the light or intersection, accelerating, I will feel that it kind of clicks 3-4 times as it is pulling out. It feels like mechanical resistance, or some sort of unlocking sound. Only will hear as I lightly tap the gas pedal to get out. It is very difficult to explain to the dealership, and unless they have been driving a Jeep for a long time, even the tech at the dealer won't know what I am talking about. From the day I bought my KJ it always had ultra sensitive gas pedal. Touch and it gets off, and when something is different, you feel it immediately. It does feel like something is sticking and rear of the vehicle is trying to break free, however there is no resistance against movement of the vehicle. Just feels like there is since something is rubbing or clicking...

I wonder if it can be checked by lifting the jeep at the shop and then applying gas while rear wheels are airborne. See if it does anyting?

_________________
NYC L.O.S.T.# 022174 -
Check out my CarDomain

sounds like you have have the same problem!

_________________
The most repeated sentence I heard from my dealer was "I'm sorry YOU are not happy with our service" so it was still my fault.

Same here! I don't really hear anything I just feel it in my feet for about 10 yards or so.

_________________
-Gavin
2006 4x4 Sport ~ Dark Khaki
2.5" Rockfather II
Tow Hooks ~ HH Rear Hitch
Hella 500's

gwip Design

hmmm, then I think my problem might be worse than I thought. I can hear mine grind with the radio on . I should be getting things checked out tomorrow. Since I have a 40 minute drive to the dealer I hope to recreate the sound.

_________________
'02 KJ Limited 4x4, trac-loc, factory skids, self installed rear hitch, trailer breaks, & trans-cooler, custom crossrails/canoe rack.

Well, I went on my 40 minute drive to the mechanic. Got the KJ to make the sound at the two stop signs right before I got there, but once I was there and had a mechanic in the car, nothing. Not a peep from the rear axle. Went ahead and had them put full synthetic fluid in with the limited slip additive. They also didn't see anything visually wrong or find anything unusual.

Good news is that after the long drive back home, I wasn't able to get the axle to grind like I usually can after a long drive. I don't know if it's fixed, but so far it seems to be doing better. If I don't bring it up again in a couple weeks, you all can probably assume changing the fluids fixed my troubles. Thank you everybody for the input.

_________________
'02 KJ Limited 4x4, trac-loc, factory skids, self installed rear hitch, trailer breaks, & trans-cooler, custom crossrails/canoe rack.

GregB, Great news!

My Redline Synthetic oil will be in the post today and I will change it this weekend, I'm looking forward to a grinding free future

_________________
The most repeated sentence I heard from my dealer was "I'm sorry YOU are not happy with our service" so it was still my fault.