My 2003 4x4 is coming up to 15000 mile service and the service book the dealer gave me has draining the front and rear axles and replacing the synthetic gear lube. ( and this is scheduled every 15k) . The owners manual says there is no scheduled service unless extreme conditions are involved . My truck has seen none of these. I am used to draining axles with standard gear oil every 30000-50000 miles and longer with synthetics. Any thoughts from the group on this. And for humor the dealer wants $189 per axle.