2002 Jeep Liberty Rear Differential Leak, help me please?

I have a liberty which I purchased used and seems to run fine. However, today I discovered that around the rear differential box is all wet on the bottom, evidence that the fluid is leaking out. Is this likely a gasket issue or are we talking about something more involved? The vehicle seems to shift fine and no slips, only problem I notice is when shifting out of park into drive or reverse, it seems to "launch" in whichever direction you shifted into and also kind of a thump noise. I was told this is characteristic of this vehicle and there was nothing to worry about. True? Perhaps just a coincidence? Not sure. any help on this would be appreciated. Thanks!

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  • 1 decade ago
    Favourite answer

    A rear differential leak at the differential housing is one of 2 things; either the differential cover was not sealed properly during a diff oil change or the pinion seal is leaking. To find out what’s going on, all you need to do is look at the differential housing.

    If the underside of the housing is wet from where the drive shaft enters, it’s the pinion seal. This type of leak if found early, can be rather small and may only wet a small portion of the failed seal and differential housing. If found in later stages, the leak can wet the underside of the diff all the way back to the rear differential cover.

    Here is a picture of a leaking pinion seal to help explain:

    http://images.jpmagazine.com/featuredvehicles/154_...

    If the seal on the differential cover is leaking, the pinion area of the diff housing will not be wet. You will see most of the leaking fluid gather near the bottom of the differential cover. The cover itself may or may not be wet depending on how bad the leak is.

    Repairing the leaking diff cover seal is a rather easy affair:

    1 Grab a catch pan

    2 Remove the cover. On the liberty its 10 bolts that hold the cover on. You may have to smack the cover with a dead blow a few times to get the cover to come off. DO NOT BEND OR DENT THE COVER. The RTV used can make the cover stick in place.

    3 Allow the differential to drain

    4 Scrape the old RTV gasket off of the housing and the diff cover.

    5 Use a can of brake cleaner to clean out the differential and pan.

    6 Apply fresh Red RTV all the way around the cover (a bead about 1/4 to 3/8 in thick is ideal)

    7 Reattach the cover and torque the bolts to spec (25-30 FT LB)

    8 Let the RTV setup for about 5 min then remove the diff fill plug (its rubber, pry it out with flat screwdriver)

    9 Fill the differential with the recommended Mopar 75W-140 synthetic gear lube, until the fluid weeps from the fill hole.

    10 Put the plug back in, clean up, and you're ready to rock

    If the pinion seal is leaking, it’s a bit more evolved. In order to remove the pinion seal, the drive shaft, pinion nut, and the yoke must be removed. Because the Chrysler 8.25 differential uses in the Liberty uses a crush sleeve to set pinion bearing preload, this setting can be disturbed by removing the nut. If the nut is over tightened when it is reinstalled it will ruin the pinion bearings and possibly the ring and pinion. If under tightened, it could loosen, causing catastrophic failure, either way, if it’s not done right, bad (expensive) things happen. If this is your problem, I’d recommending having it done by a reputable dealer, or drive train shop. The seal is $20, the nut is $5, with labor you should be out the door for $125-$175 depending on the shop.

    Oh, the "thump" is normal. Theres a lot of back lash in the 4x4 system, its just taking up the slack. Dont worry about it.

    If you have any more questions, just ask!

    Source(s): 4 years as a Chrysler Jeep technician, and over all Jeep nut.
  • boarts
    Lv 4
    4 years ago

    2002 Jeep Liberty Drive Shaft

  • 1 decade ago

    Coincidence. The thump and the "launch" would be the transmission acting all jeep-like.

    Might be worth it to have the diff gasket replaced. sometimes it's just a matter of loosening the bolts and applying sealant, nothing major. the thing to remember is that if lubricant is leaking out, if you off-road it, water might leak in, which would be a lot worse. so have it inspected and resealed, it'll last longer.

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