Sithspawn will do a much more thorough job but I used a small 3/4" thick plate and fin B&M cooler (I'll post the model number when I'm not at seaworld). I purchased 20 feet of Edelbrock -6AN stainless steel braided hose. I went with braided to eliminate kinking since it was going to be run through some decent bends. I went to the hose store and pieces together a 1/2 inch to 3/8 reducer that also had a 1/4 inch hole for my temp gauge sensor. I also purchased a straight 1/2" to 3/8" barb reducer for the connection back.
I cut the hose exiting the stock transmission cooler, inserted my custom reducer, ran the braided hose down the drivers side, across the crash beam, to the passenger fog area where the cooler is, then back the same way and back into the transmission using the 3/8 to 1/2 barbed adapter and the existing stock hose still connected to the transmission inlet. I put hose clams on every connection and used tons of zip ties to make sure nothing was going to move or get in the way of anything else. I then cut the braided hose on the return line on the crash beam and inserted a filter. Wired up the temp gauge, added 1/2 quart of WS fluid into the transmission using a fluid pump and done. The gauge isn't the best placement since it's already after the stock cooler but I was lazy to splice it before the cooler. Word of warning, wear gloves with the stainless hose - the ends can hurt
