Getlemen. i require your assistance. I'm currently changing my ATX tranny (myslef). I bought Castrol Syntec 2 moths ago, and afer some dissapointing discoveries on this site, decided not to use it anymore. I'm looking at either Red Line Syntec tranny fluid or B & M synthetic trick shift tranny fluid. The issue here is that Redline's fluids only come in Dexron II (High temp or Racing fluid) or Dexron IV. Are the numbers different because these fluids are formulated for performance, or are they different because they are formulated for other applications that require Dexron II or IV. Thats a bit confusing. basically, the 6 uses Dexron III. Can I use either Dexron II or IV from redline without any consequences?