Just bought a Chevrolet Silverado 2500HD 6.6 Dmax/ally CCSB Z71 with 39K miles and factory warranty.Spoke with allison and they stated that Transynd is "the best,most durable transmission fluid with millions of miles of data" for any allison including my A-1000. Im going to perform a cooler line exchange and change out the spin on filter next week. Transynd is expensive as $%@#, but what isn't these days! From what I've read, GM use to own allison, and started recommending DEX fluids in the A-1000's. Allison claims DEX VI will work,but it is definatly a shorter drain interval fluid, and not something they would ever use in the commercial grade transmissions. My truck specs DEXRON VI(had the newer seals),but Transyn(TES-295?DEXIII) seems like a natural choice. Please share you experiences using it. Thanks!