Just would to know what you guys are running in the front and rear diffs for fluid. Need to change mine in about 1000km.

 

ROYAL PURPLE! great stuff. hand calculated gave me about 1.7 mpg increase.

 

yeah im going to put the royal purple in mine this weekend

 

what are your thoughts on amsoil? anyone see better/worse between one or the other? any significant benefits over mobil1? I'm going with one or the other for the 60k tune up in a month or so.

 

Last 4 fillups running stock differential fluid and Mobil1 oil:

217 Miles / 14.25 Gallons = 15.22 MPG (~ 1/2 City / 1/2 Highway)
342 Miles / 22.15 Gallons = 15.44 MPG (~ 1/2 City / 1/2 Highway)
184 Miles / 11.43 Gallons = 16.09 MPG (~ 1/3 City / 2/3 Highway)
212 Miles / 12.85 Gallons = 16.50 MPG (Pretty much all Highway)

This comes from my work log, I have to fill up and record everything on every trip.... Anyway, switched to Amsoil Differential fluid and Engine Oil at the same time, however only had 2 logged fillups before I got my Edge programmer:

285 Miles / 16.44 Gallons = 17.33 MPG (~ 1/3 City / 2/3 Highway)
141 Miles / 7.74 Gallons = 18.21 MPG (All Highway)

I was happy with what I saw, and definantly think it's worth the extra money... I got my programmer after that and have since broken 20 MPG's on all highway fillups... I think I've tapped all the mileage I'm going to get out of my truck....