My wife's Blazer needs a fluid flush. Is there any reason to NOT simply use store-brand D-III ATF? 1986 K-5 Blazer with Tatonka Products "Bummer" body, originally a 6.2 diesel, now has a turbocharged Optimiser 6500 Hummvee engine. Rebuilt 700 with deep pan and a shift kit I think is B&M. NP208 T-case, 3.73 gears and 35x12.50R15 tires. Has huge tube-and-fin trans cooler that is actually a fluid cooler from an old concrete mixer truck.