I just installed B&M 70264 SuperCooler Automatic Transmission Cooler on my 97 Yukon with freshly built transmission. It took about 1.5 hrs and requires very little mechanical ability. This cooler is not fan assisted, but it keeps transmission temp. in 130 degrees during normal driving and around 155 degrees towing 4500 # boat.
This is approximately 20-25 degrees cooler than without additional cooler.