I got my Flex-O-lite 4120 Trans cooler installed today... Very easy to do but I must stress how important it is to Flare the lines that are going to the trans cooler. it is very easy to do and the Flare tool is only $10 at your local autozone. Also when you run your lines make sure that any line (rubber or metal) that touches anything metal... make sure that you cover it with something. I just cut open some 3/8 rubber line and put it over the line that comes in contact and chaffe against anything.
Trans temps after an hour of driving in city and highway are below what they were since I got the H2. This cooler is rated for 20,000 lbs GVRW the H2 weighs in at 8000 lbs give or take so that means with this cooler you could tow an additional 12k I do not plan on doing that so I think I am set. I will however get the bypass because here in Wisconsin we get some cold temps.
Here are the completed pics of the FAL 4120 that I got for $53 shipped from summit and comes with everything needed for the install. Minus the tube cutter and Flaring tool.
