Changing fluid in my Silverado

[Positraction Action]

I want to change my transfer case and rear end fluid in my 04 silverado 1/2 ton. The book calls for some expensive fluid, does anyone no if I can just use some regular Mobil synthetic or anything else. Or just use some type of additive. It's the auto transfer case and the locking rear end.

[1fastdeuce]

If it's the push button auto 4 wheel drive transfer, you have to run the fluid it calls for.

[Hille]

I'd use the GM stuff for the transfer case. It can't be that expensive.

[STL2SLO]

Auto Trac 2 fluid for the t case- it only takes 2 quarts. And any good 75W90 synthetic for the rear diff.

[Positraction Action]

Do I need any kind of limited slip additive for the rear end or just straight synthetic lube.

[import assasin]

go with whatever the manufacturer calls for. there are aftermarket substitutes but just to be safe i stick with manufacturers recommendations.

[UPdragracer]

Do I need any kind of limited slip additive for the rear end or just straight synthetic lube.

I'm sure you will need to have some kind of additive for the posi diff .

A.K.A. friction modifier

[1fastdeuce]

Why use synthetic if you have to put in a friction modifier? Kind of defeats the propose of the synthetic doesn't it?

[YAV8]

Synthetic oils are the base stock from which the lubricants are made, friction modifiers are added to the base stock along with other additives to make the correct lubricant for the application. Just because it a synthetic does not mean it has the best additive package. If its off the shelf at your local walley world its a upgrade. If you want the best, you will need to go with a speciality lube made for you appliction, this will cost a little more but is a lot better then the self lube.