Diff fluid change interval

[Robertaz]

What is the recommended fluid change interval for the front and rear differential when using Mobil-1 (SAE 75w-90)?

[JimWilson]

GM has no change interval that I'm aware of, so they must think it lasts forever. Anyone with an ounce of common sense knows that's not true.

I change it at 3K, 50K then every 50K after that. If you're compulsive (like me :D ), tow a lot or abuse (or use hard) your truck then that's probably a good system to follow.

That's also the schedule I use for the tcase and tranny fluid.

[jbplock]

The following thread has some good info.

http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=7&t=000607&p=

[Robertaz]

Great! Thanks alot. I did the rear last year at 1000 miles and will do the front tomorrow at 22,000. I'm using Mobile 1 but having difficulty locating it. Pep Boys carries it @ $8.99/qt. and Checker @ $6.99 but they are usually out of stock. I bought the last one today now I have to go looking for one more quart @ the $6.99 price. I'll schedule a preventative maintenance change every 50,000 miles from here on. Thanks again.

[Tsckey]

Kragen carries it out here and it's right between at $7.99/qt. I bought the last three from the local store last night.

[Lone Eagle]

Robertaz, All the Autozone stores here in Utah carry it. Later! Lone Eagle ;)

[Robertaz]

I tried a couple Autozones here in Phoenix but all they carry is Valvoline and some off brand names. Walmart carries Valvoline and a few others also. I'll try another Checker (Kragen) tomorrow.

[JimWilson]

What about Amsoil or Royal Purple? Both make good synthetics too.

[dmaxalliTech]

Just came across this info regarding Limited slip rear axle service. Its under the Maintenance heading in the warranty owner assistance supplement in your owners manual packet, page 6.

"All vehicles require periodic maintenance. Maintenance such as those detailed in the ownders manual are the owners expense. Veh lube, cleaning polishing , as well as items requuiring replacement or repair as a result of vehicle use, wear, or exposure are not covered. Item such as: Filters, Brake pads, clutch audio system cleaning, Coolands and fluids, wipers, tire rotate, wheel align and balance and limited slip rear axle service. It makes no mention of drain intervals, just thats its required maintenance.

[David Proske]

When I changed my diff fluid at 1000 miles it smelled horrible compared to the Royal Purple GL5 75-90 that I put in. I will pull the fill plug at 5,000 and stick a finger in there and see if it is smelly again. GM sure must set up the gear set tight to burn up the stock synthetic like that.

[Raptorrider2001]

Does the anti-spin diff. require an additive or can you just use the sythetic 75-90?

[dmaxalliTech]

Dave, most of the burn comes from breakin of the locker. Gears are set with about .005-.007" backlash and will wear into approx .008-.009"

Raptor, no additive is required on this axle. Synthetic lube is sufficient