MTX fluid is more along the lines of motor oil. Our ATX fluid has more additives in it etc, and is more along the lines of power steering fluid. This allows us to run the fluid longer and keep our tranny relatively cleaner.
Castrol ATF+3 will run just fine in our trannies. MOPAR ATF+4 is out now, and is a much improved fluid. AMSOIL is the best fluid for our trannies, but is so expensive that not many people run it. Even John at IPT uses a Dexron/Mercon with lubeguard additive.
