Has any one heard of DR fluid for your diffs? I was told by the parts guy at my local dealership, I know, but they carry Royal Purple too. that the only oil I can use is this DR stuff at 29 bucks a qt. I was looking into putting RP Max Gear in but he was talking about warrentys and stuff, so I thought I'd better ask someone I trust.

 

You need to run a 75W-90 synthetic per the factory manual that came with the truck. You don't need anything special.

 

Check Amsoil, they got what you need. My truck tranny/diffs call for 75-90 synthetic, they sell it all day long at Amsoil for http://www.amsoil.com/storefront/fgr.aspx You can look on the right side of the screen, under product lookup guides, click auto and light trucks and enter year of your truck, model etc and it will show you all the fluids you need. Been running Amsoil in the engine for over a year now, working on converting everything over as needed. Went 14k on my last oil change. Ran from December of 09' to end of August 2010. Saved me several hundred dollars on the conventional 3000 mile junk.