A903 3 on tree trans fluid

It seems Mopar used the climate to dictate what fluid to use. ATF doesnt get crazy thick in cold weather so they use that in northern climates and out the door off the line. As it states it can be replaced with 90w or even 140w in warmer climates. There are no syncros in a 903 iirc so there is no special ingredient. Gear oil most definately in the rear. Dexron is backards compatible to all numbers, the highest Dexron is usually 100% synthetic, not needed in a manual.