Thanks for the write up! It was very inspiring! Since I have the big block powered truck with the 4l80E I decided to step up to the larger B&M 70274. To get that monster to fit all I had to do was shift over one mounting hole and then drill a new hole for the bolt on the right. I drilled the hole just a tiny bit high to tilt the cooler out of the way of the center latch support. I haven't fabbed a top support yet, but once that is done I'll be able to go on a drive and see how my tranny temp is effected.
Side note: I did have to cut a small corner off the lower valence for driver side (right side of the picture) adapter to fit
Very nice install! That thing is a behemoth!
I would leave the cooler in the radiator plumbed in, as it not only cools the fluid but warms it in the winter so that you don't run into pressure issues with the fluid being too cold and thick. You won't have the mounting brackets already present on the truck, so you can install it wherever you would like, either with a custom fabbed bracket or with the ties included in an install kit. You will want to run the lines from the outlet side of the radiator trans cooler into the aux cooler, and then back to the trans. I recommend mocking up the install, measuring the length of lines you will need, and having a hydraulic shop make a set of lines with a steel braided line. Hydraulic line is far superior to the usual rubber hose you find in the install kits, and can take high temps, fuel, oil, and abrasion much better. Cheap insurance compared to blowing a line. Also makes for a much cleaner install.
As far as Efans go, they work, but there is a reason that the 3500 trucks still use a mechanical fan, and that is that most Efans will not keep up with the amount of of airflow needed for proper heat rejection under load. I recommend using a late model style 9 blade fan and a heavy duty clutch. Thermal clutches disconnect the fan at highway speeds, so you really aren't going to gain much fuel economy under lightly loaded cruising conditions, as the ram air effect provides most of the airflow. Lift and tires are going to hurt fuel economy far more than an Efan would ever help, and power gains would be insignificant, as the fan centrifugally disconnects at high RPMs where horsepower is made. I would, however, invest in a 454SS style radiator. That should give you all the capacity you need. I have one in my Suburban and have a very hard time getting the truck much over the thermostat's rated temp.
