I've been using the Edge Insight since 2011. When I contacted Edge about it they said it wasn't really made for the E Series but that I could return it if it didn't work out. It's been great. HOWEVER I have heard rumors to never update it because it will loose most of its functionality on a van. IDK. It plugs into the OBD2 port and reads from the ECM sensor that's in the trans valve body.
Ignore the arrow, it's from a different topic.
When I got my van (used) in 2010 the transmission that came with it is suspected to not be the original and not right. That trans was hot like lava all the time. 225-240 highway driving and 250 on a slow dirt road. After a year or so the torque converter wouldn't lock and put the trans into burnt eruption. When that happened in Blythe, at midnight, in 101 degrees, covered in burning ATF, I rethought my life.
So this is the new, as of 2011 new, set up.
I took this photo to actually share the sad state of my off road lights.
5r110 Transmission (John installed it and did some programming)
Schaeffer's All Trans
fluid. (John said,"use it and no questions")
Tru Cool Max
45k btu cooler (I was trying to copy BadgerTrek)
behind the cooler re-purposed from the 80's off an old 4x4 I had. I don't know the brand or size. Maybe 10" but powerful and loud. Fan is controlled by a 180' thermostat plumbed into the inlet of the cooler.
installed this summer which helps everything especially A/C
Just a note the path of the trans fluid is still through the radiator heat exchanger then through the Tru Cool then back to the trans.
Now my trans temps are way cooler. Around town/highway/up Vail Summit it's 160' (trans thermostat open temp) to 180. Highest I've seen this set up was 196 which was up a grade, 96 degrees outside, pulling a 5k lb trailer. I hear the trans fan cycle on at 164' on the gauge so the fluid entering the Tru Cool must be warmer than where the sensor for the ECM is.
Anyway, sorry for the long reply. My story is no mater what way you decide is best for you, Monitor those trans temps! And I feel anything prolonged over 200 degrees is asking a lot of your ATF.