Changing rear diff oil...

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Jul 13, 2003 | 05:42 PM

Hit Man X

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From: North Texas

Changing rear diff oil...

Okay, what is the recommended weight of the oil I need back there? I'd guess 75/90.

Oh yeah, also does that gasket go on dry or on with a sealant of some sort?

What is the torque on the bolts...10ft-lbs?

Thanks!

Jul 13, 2003 | 06:59 PM

GammaDriver

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From: Southeast FLA

Changing rear diff oil...

Hit Man X, while I believe in the use of the best lubricants throughout a vehicle, and thus use fully synthetic products, I have to tell ya that I have never felt any noticeable horsepower/drive-ability improvements from any of it except the use of synthetic gear oil in the differential.

I only recommend Mobil 1 Gear Oil for rear-ends after my experience with this truck. (I don't beat the truck, so I didn't notice it racing or around town - but instead on the open highway where I noticed the acceleration (without downshifting) at 65-80 MPH speeds had improved markedly.)

When you do go to change it, have a small mechanic's magnet on the end of a rod to fish out all the particles from their pools and settling places. Spend some time cleaning out the differential as best you can with the magnet (cleaning off the magnet occasionally with a paper towel).

I do not know the proper gasket procedure, but I used what appears to be a gasket 'treatment' that I don't think congeals up like gasket-makers do.

I just torqued it to feel (as it is just a cover like a valve cover) in a star-pattern (like lug nuts), so I can't help you there.

Best,

Jul 13, 2003 | 07:12 PM

Hit Man X

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From: North Texas

Changing rear diff oil...

I have Syn fluids in my Front diff, Rear diff, and Transfer case in my Z71 and they hold up very well.

Thanks for the tips, it didn't even cross my mind to clean out the diff first!

Jul 13, 2003 | 07:32 PM

MustangGT221

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From: Topsfield, MA

Changing rear diff oil...

Don't use synthetic on an axle that has had regular. Axles designed to use synthetic have a special tag on them like the other info tag already there. Just re-fill with a normal lube, not synthetic or it will leak. There is no gasket, just gasket sealer and a bead around the edge. Take all the bolts off, but leave the top one on but loose until most of the fluid has drained out, then remove the top bolt and pull the cover off. Your owners manual will tell you what lube to use.

Jul 15, 2003 | 08:55 PM

natewoz

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From: MN

Changing rear diff oil...

You can put synthetic in an axle that doesn't say it needs it as long as it has the same viscosity rating you're ok. In axles like an 8.8 limited slip you must to have synthetic because it's the only oil that holds up in the higher temps and pressures between parts caused by the limited slips.