I have a 2001 Ford Ranger with 117,xxx miles on it. Since new, this vehicle has always had all of its fluids changed every 30,000 miles. At 90,000 I changed all of the fluids to synthetic - Mobil 1 ATF in the auto tranny (full flush with filter change), power steering flushed with mobil 1 ATF, transfere case has Mobil 1 ATF, front diff has Mobil 1 75w-90, rear diff has Mobil 1 75w-140, brake fluid flushed with Valvoline Synthetic DOT 3-4, and Zerex G-05 in the cooling system. Do you think these fluids need to be replaced at the same interval, or should extend their change interval? The truck runs very well, and has no known problems/issues. Thanks in advance for any help!