Delayed posting so I could test our new Trans cooler system. First, I have to thank Chris (unreng) since he inspired my selection and was very helpful in answering many questions - His build was the motivation I needed.
Had it installed Sept 2022 but hadn't had the opportunity to take the van out in different scenarios to see if it it was everything I hoped for. Took a couple months to 'dial it in' (achieving the proper thermostat setting since initially it ran too cool), but can now say the installation of the
Derale 15870 Hyper-Cool extreme Trans Cooler, and a manual dash controlled fan over-ride switch
is a game changer! (I haven't even needed to use the fan over-ride, although did test it a couple times).
I've driven the van now in many scenarios including a couple long slow steep uphill crawls, and long uphill highway sections which in the past both challenged my Trans temps - never went above 190 degrees (same roads I've hit 225 - 233).
We left the OEM trans cooler intact, and mounted the Derale cooler behind the transfer case & above the rear driveshaft. It's spliced into the Trans cooling system so it first accepts fluid from the transmission, then continues to the OEM cooler - An unexpected reward is it has also lowered the Coolant temps, seems it's taken some of the heat out prior to reaching the radiator.
The shop I use also fabbed a Drive Shaft safety loop with a thin protective plate (designed similar to a mini skid plate positioned between the drive shaft & cooler) which will provide some protection for the cooler from road debris - just haven't been back yet to install.
Definitely one of my favorite mods!
Pic shows location of cooler mounted (can see it in the upper right; prior to rear diff):