Rear differential went out

MuzzleFlash40 · May 25, 2015

The wifes 2004 Grand Marquis had a pinion seal leak a year ago. Didn't notice anything until I started to hear a slight whine.

Changed the seal and fluid, but still had a slight whine at highway speed. Well it lasted another 35k. The wife said she heard a noise on her way home and the rear end started grinding.

I bought a used unit out of a wrecked 2006 with 25k miles on it to replace it. I'm going to have it filled with mobil one and hope to get another 165k out of it. At least a couple more years until she gets a closer job, to make it worth getting her a new one.

Otherwise this car is great. I don't have to add but maybe .5 quarts during the 7.5k OCI, trans shifts silky smooth. No rust. Hope this works out.

Olas · May 25, 2015

Is there any guarantee with the used part?

Falcon_LS · May 25, 2015

IIRC there was a recall on the rear differentials on '03-'04 MYs.

Rob_Roy · May 25, 2015

Originally Posted By: Falcon_LS
IIRC there was a recall on the rear differentials on '03-'04 MYs.

Yep, axle shafts were not properly hardened and the axle bearings would cut a nasty grove in the axle. Usually the axle seals leaking was the tell tale sign, but the amount of filings/debris in the oil probably ruins everything if run long enough.

The used axle should last a long time if you keep clean oil in it.

DoubleWasp · May 25, 2015

Make sure to take care of those u - joints. Loose u-joints destroy pinion bearings, and then the seal is not far behind.

RF Overlord · May 25, 2015

*deleted*

NHGUY · May 25, 2015

Sure the axle ratios are the same??

SwampSurvivor · May 25, 2015

Probably. Pretty much every Civilian Vic had 2.73 gears in the rear. The police package would have 3.27 or 3.55

MuzzleFlash40 · May 25, 2015

Yeah all of the civilian models had a 2.73, unless you get a performance package or police with a 3.27 - 3.55. It comes with a 3 month warranty.

I picked up a new pinion seal and two new u-joints to go with it.

SwampSurvivor · May 26, 2015

Does taking the yoke off to change the seal affect preload? That may have caused the other failure ...

I have a leaky diff on the Cherokee. It uses the pinion nut to set preload. Unless I get it perfect, I'll lose the preload.

Not that it matters ... I had to take the yoke last year to replace it.

Rear differential went out

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