All you need is a small tranny cooler. Mine is a 10,000 lb GVW rated unit made by Flex-a-lite. It's 5" x 12" and 3/4" thick and the fluid makes four passes through it. The PN is FLX-4110 in Summit Racing and it's $25.95. You can save money on shipping though, and go to Autozone or parts store and get it. I think the one on Stephen's ORD Jimmy is slightly bigger, maybe 7" x 12"? Hope this helps.
Will