[x96mnn]

My father in law has 2005 Jeep Liberty Limited and at 80,000KM the rear-end needed new bearings and seals. Then at 90,000KM the transmission needed to be completely overhauled. Now he is finding a vibration in the rear at 100K. Has anyone else experienced similar problems with the KJ style? Driving pattern in 90% highway at 100 to 110KM per hour. He owns a small camper, 2000pds that is hauled and a utility trailer. He is the second owner and was told when he bought it that the previous owner had towed a camper weighing 4000pds during the summers. The Jeep was only 2 years old we he bought it but could the towing by the previous owner contribute to the issues he is having now.

[LibertyTC]

My guess these vibrations are felt at highway speeds. Is there a rubbing noise or slight growl sound? Brakes can also simulate vibrations.
Does the rear differential have the Trac-Lok?
I would recommend that you or a shop, 1-check rear Universal joint and 2- pull the differential cover and have a look in there, replace with synthetic gear oil, see if there is wear on the teeth or clutches. If it is a Trac-Lok differential the clutches are probably worn out (they don't last that long) and the Chrysler bottle of friction modifier has to be installed for Trac-Lok rear ends.
How often has the diff fluid been changed?

[x96mnn]

Thanks for the reply, all was completed about 20,000KM ago, main question is have others had issues with the KJ tranny and rears. I do not recall seeing any and visit here often.

[LibertyTC]

If you are trailering, Chrysler specifically states that a synthetic gear lube on 75W-140 to be used.
I would consider changing diff oil again if you did not use synthetics. I Normally change the diff oil every 25,000km with synthetic.
You did not answer if you have a Locking Trac-Lok differential, that absolutely needs friction modifier added as well.
If you do have Trac-Lok those clutches don't last all that long 40,000km..aprox before mine went.
Does anyone have the Chrysler Part # for that small bottle/tube of friction modifier handy, I need some..

[valvestem]

Originally Posted by
[B

Does anyone have the Chrysler Part # for that small bottle/tube of friction modifier handy, I need some..[/b]

You should be able to find the friction modifier at any well-stocked auto supply house.

But I did come up with this: Chrysler 4318060 Friction-Modifier, if you want only Chrysler.

[LibertyTC]

Thanks Valvestem, Heading out for shopping now....why does my weekly shopping list always contain something for the KJ?