AABEN, Well that's just it. The book, or Owner's Manual say to change the front and rear axle fluid every 15K miles under Schedule "B", however under Schedule "A", which is more where my truck is driven, it never says to change the fluid but to merely check the level of the manual transmission and transfer case. It never says to even check the fluid level of the front and rear differentials. I may tow heavy only 20% of the time.
I don't mind changing the fluid more often, but the Owner's Manual is very vague between Schedule A and B.
Same applies to Manual transmission. Schedule "B" says to change fluid every 75K miles on the G56 manual transmission only. No schedule is made to change the fluid on my transmission, which is the NV5600.
What gives, george