This is nothing more than the product of the power of advertising and perhaps preying on folks with too much money in their pockets? Do you really think that the OP is of the ilk who change their own rear end/differential fluids? The engineers who designed the truck know exactly how much oil is needed for cooling even under the most arduous of conditions. Do you really think that the OP is going to monitor the differential temperatures of his rig? You would be lucky if an owner pays attention to or knows what an EGT is! There is plenty wrong with more if the more is only to pad the wallets of the geniuses who make us believe that we just gotta have it.
BTW OP, are you SURE that the spec for the front differential is ATF+4?
Cheers!
Mike
