ok so is atf-4 the same stuff across the brands? im coming up on a trans filter change and was gona use the cooler line method and replace all the fluid in there. amsoil is twice as much as mopar atf-4 and i think valvoline also has an atf-4. should i be worried pickin one over the other? seems to me that there might be some sales pitches in on atf-4 over the other....