...so a few days ago a strange humming sound and vibration started coming from underneath my Libby when I decelerate. First thing that came to my mind was a Universal Joint. Under the jeep I go later to find them to be perfectly fine. Time to take it to the shop. Its fresh out of warranty so I wasnt taking it to the stealership. I took it to a local shop thats owned by a Jeep guru. Next day I get a phone call...your differential is bad..HUH?? A chrysler 8.25 bad at only 81,000 miles!? I was in complete dismay. I had just replaced the fluid with Amsoil last year and it looked fine when i had the cover off. He called a salvage yard to get a price on a used rear end...$1500!? Sounds a bit ridiculous to me. Im checking into getting it rebuilt instead.
Anyone here have problems with theirs? I thought the 8.25" was a reliable rear end...am i mistaken?

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05' Liberty Sport CRD-
Magnaflow muffler
Gutted Cat
SEGR
EHM
New Thermostat
New boost hoses
New MAF, MAP and Boost/Intake pressure sensor
V6 Airbox Mod with K&N Air filter
FIA grill cover for winter
225 75 16 General Grabber AT2s
98k miles and counting

2007 Honda CBR 600rr:)

What's 'Bad' about it?
bearings? pinion seal? Bent axle shafts?????
did it get water in it?

a good shop should be able to totally rebuild it for $1500 - not just pick up a used one.

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2005 CRD
stuff
Skeptic quod gratis asseritur, gratis negatur

Highlighted is what went wrong,sorry to say.Spent a few hours with some oil tech guy's the other day and there is a reason why synthetic gear oil is being used(to satisfy CARB) and why more frequent gear oil changes are mandated by the manufactures now even though synthetic gear oil is being used in newer diffs.Basically they needed to lighten heavy components by using less dense materials and the diffs are one of those areas that have been lightened,with the synthetic gear oil you must change every 15,000miles or trouble can happen from high heat that synthetic gear oil can not conduct.Synthetic gear oil is not better then dyno gear oil,it is actually worse at pulling heat away from the gears and bearings in diffs(works great in engines though).Thank CARB and change the gear oil often with synthetic or things tend to self destruct when ever they want.

I guess I'm glad I've stuck to the Schedule 'B' maintenance schedule even though I didn't really understand why it required a rear diff lub change at every 12,500 when Schedule 'A' never required one.

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2006 CRD Limited Dk Khaki
InMotion S-II, GDE TCM, Cummins Lift Pump, Mishimoto CAC hoses
Cooper Discoverer ATP LT245/75, Rola roof basket, JCR S3 sliders
OME lift+JBA UCA's, custom front hitch receiver, Mile Marker winch
All J Products rear cargo shelf
Sips biodiesel as if it were 12 y/o Scotch

Funny thing is no one can ever fall into schedule "A".

I've got this buzzing, vibrating kind of sensation when I decelerate too. Been wondering what on earth it could be.

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2005 Stone White KJ Limited CRD 4x4
Off-Road Pkg
Trac-Lok
Emu 790s/948s
Skyjacker H7088s rear/Bilsteins front
15x7 Black Rock Lobos/31x10.50 Firestones
GDE HOT Tune + TCM Tune
Euro TC
CB radio
Thrush Turbo muffler
AEM DryFlow filter

I'd be there if the temps wouldn't get down to below 32*.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

Same thing, shortly after I bought the Jeep (From new)the rear end started acting up. I opened it up to take a look and after 10000 miles I was shocked to see the state of the gear lube, black and ugly! The magnets also had an above average amount of iron filings on them. I removed the factory magnet cleaned up the gears for inspection, drilled and tapped the bottom of the housing to make oil the frequent oil changes less of a PITA and welded a proper bung and plug in the cover. I glued a rare earth magnet to drain plug, refilled with gear oil and a boundry lubricant additive. I faithfully change it out every second oil change. So far so good, and no noise or vibration!

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06 LIMITED 100000miles, MAGNAFLOW, HOMEBUILT CCV FILTER, POLAR PAD, 02 AIRBOX, CUMMINS LIFT PUMP, SEGR, PILLAR GAUGE POD, CAT FILTER MONITOR, SPYDER TRAX, ALWAYS A LITTLE TWO STROKE OIL OR BIO, WATER/METH INJECTION

^ The magnet in mine has always had that heavy sludge looking stuff on it. No filings at all.

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2006 Sport CRD

Could the Aztecs have known, that in 2012 after a 4 year experiment, our country would cease to exist?

I atribute it to sloppy clean up after milling from the factory.............. I hope.

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06 LIMITED 100000miles, MAGNAFLOW, HOMEBUILT CCV FILTER, POLAR PAD, 02 AIRBOX, CUMMINS LIFT PUMP, SEGR, PILLAR GAUGE POD, CAT FILTER MONITOR, SPYDER TRAX, ALWAYS A LITTLE TWO STROKE OIL OR BIO, WATER/METH INJECTION

I think I changed gear lube on an XJ back in 2002, don't think I've done it since then.

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http://www.Colorado4Wheel.com
"Its not about what you can DO with your Jeep, its about where you can GO with your Jeep."
Knowledgeable - But Caustic

im actually not sure yet what exactly the problem is..the mechanic just put a scope to it while it was on the lift and said its growling from inside the pumpkin..he said it was a waste of time to tear into it since he doesnt have the correct tools to repair it anyway..not sure what im going to do yet..im still drivin it for now.
Looks like i am going back to dino oil in the diff..thanks for that input.

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05' Liberty Sport CRD-
Magnaflow muffler
Gutted Cat
SEGR
EHM
New Thermostat
New boost hoses
New MAF, MAP and Boost/Intake pressure sensor
V6 Airbox Mod with K&N Air filter
FIA grill cover for winter
225 75 16 General Grabber AT2s
98k miles and counting

2007 Honda CBR 600rr:)

actually I can, mid georgia, average temp is not over 90 or under freezing, 30 mile commute (10 miles at 55 then 20 at 70) with never any traffic and two stop signs, one traffic light!

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2005 Liberty CRD Limited
Light Khaki

I don't buy the "poor heat transfer" argument. I can't possibly fathom how the heat capacity of the synthetic versus dino base oils being significantly different...this quantity should be identical for all intents and purposes. If the heat transfer was that bad, no one would ever put synthetic oil in an engine.

One of the reasons synthetics are often touted is for their improved lubricity or slipperiness. Now if that is true, they should lessen heat build-up due to less friction. Another reason is for the flatter viscosity vs. temperature curve.

Now, there could be something to the argument of dino lube being better than synthetic lube due to the ability to carry heat, but it's going to take something more convincing than "it is because these lube guys said it was."

Only applies to gear oil.Call Currie or Hi9(both highly reputable axle builders) and ask about synthetic vs dino gear oil,you'll get alot of good info.

I don't buy it either. Those guys are axle builders, not oil companies. Conventional and synthetic oils have nearly identical specific heats, densities, and thermal conductivities. That sounds like one of those internet legends that circulates and no one can ever find the evidence to support it.

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05CRD: GDE Hot ECU & TCM tunes, Provent, Cat filter, Facet lift pump, TransGo kit, Florida TC, Samcos, stainless brake lines, HDS thermostat, Renegade light bar,
RL super sliders, Bilstein adjustables, Al's Gen 4.5 Arms, 235/85-16 Duratracs, DTT rear, Elocker front, EVIC+TPMS, Turbo timer, McNally pillar gauges, Weeks Stage II kit.