Originally Posted by gomer_110

Redline synthetic fluid. The key to heat rejection is surface area. This tube and fin just doesn't give the fluid enough surface area to give up it's heat. Fluid rejects its heat into the tube which then gives up its heat to the fins and then the fins into the air.

The stacked plate coolers offer greater surface area for the fluid to give up it heat.

Only difference between tranny, ps, and oil coolers is what the manufacturer decides to call them. A heat exchanger is a heat exchanger regardless of what you want to call it.