Hi Bill, I also use a double pass heat sink type cooler (no trans cooling in my PRC radiator) plus I also use a Derale remote tranny cooler with a electric fan on a temp sensor switch. This was done for just piece of mind so I would have no worries about heat claiming my turbo 400's demise. Old adage is "better safe than sorry" and trouble free hot rodding is so much better than being stuck along side the road in the middle of now where.