Slater

I bought a 2005 Grand Cherokee Laredo new. It now has 155,000 miles. I have always kept it in my garage. The paint, interior, and headlight lenses look like new. Because of a noisy rear end on deceleration I took it in to an automotive repair shop two years ago (24,000 miles ago). The shop installed ALL new internal parts. It is a Trac-Lok Limited Slip rear end. It has operated without a whine or noise of any kind since then. However, I installed a new set of BF Goodrich All-Terrain tires at that time. They wore completely out in the 24,000 miles. The previous set of new BF Goodrich All-Terrain tires lasted 49,000 miles. I always rotate my tires when I change the oil at 3000 miles. I can't help but think the Limited-Slip rear end is too LIMITED. Is that possible? If so, can it be adjusted? I have always done all service and maintenance during the life of the vehicle except for the rear end overhaul. I'm an aircraft mechanic and I treat my vehicles like airplanes and maintain them on the manufacturer's recommended maintenance schedule (can't help it). I have always added the rear end gear oil additive at each change wanting to protect the limited slip components. What if I change the oil and leave the additive out? If it's causing my tires to wear out prematurely I don't want it to work so well. I never go 4-wheeling in this vehicle. I have fully restored a 1949 CJ-3A for that.
Your thoughts or suggestions would be appreciated. I felt that you guys would know more about this than any other source. Thanks in advance.

Slater

I would really appreciate some help with this problem. Thanks.

marcall

If I get what you are saying.....You got the rear end rebuilt a couple years ago and it still runs great and quite but you are wearing out the new tires even with regular rotations?
What kind of LSD did they put in the rear? Is it by chance a full time locking or "lunchbox" auto locker by chance? Even so they shouldn't wear out that quick, BFG AT's usually easily last 40-50,000 miles. BTW they are wearing from the rear rather than the front (Tire rotations every 3,000) is that right?

Gorillaxj

Open/LSD/Locker they shouldn't wear out that fast...

If the LSD is "to tight" it would chirp around corners on light-mid acceleration like a locker would, or at least have a vibration from the back end.

Don't leave out the Additive, the additive is a friction modifier that actually allows it to slip and not "grab as much" Leaving it out can damage the clutch packs as well as make it slip even less and create more tire drag in turns.

Slater

marcall,
Because I have no experience in GJ mods I'm unable to answer your question about what kind of LSD is in the rear end. I know they duplicated what was there previously by rear end model and VIN no. Yes, I rotate the tires at each oil change. They have worn out perfectly even across the tread of all four tires, no cupping or inside or outside wear.

Gorillaxj,
No, the tires do not chirp when going around corners and there is no vibration from the back end. And in compliance with your response I will not be leaving out the additive (truly, that was just a desperate statement, anyway).

With the tires have no unusual wear pattern and without the chirping or vibration, possibly I just got a bad set of BFGs but that's not likely either.
Any other thoughts? It has me baffled. And thanks for the responses gents.