904 Transmission Fluid Recommendation

I use the Amsoil ATF in my 2004 Dodge diesel 3500 dually and their SuperShift in my race car. The SuperShift has the firmer shift/frictional qualities of a Type F. Less slippage, less heat. My trans builder said to keep using whatever I'm using in my race car when I do bring the trans in for freshening. But synthetics are much more resistant to heat, which is the number one cause of transmission failures. If you do any "spirited" driving or drive in hot climates, lean towards synthetics.

Amsoil source & additional info: www.thelubepage