Correct, it's a diversion door. You pull the knob upward to fuel the sub. Down for the main. The door does not completely block the main when the sub is selected. If using the sub you need to fill it first, then the main. If you fill the main first it is a struggle to fill the sub.
When filling...
Averaged over 17 miles per gallon over ~650 miles. Most of the time it could manage posted speed limits. I was not in a hurry. The journey IS the destination.
After having a few days to put gear away and reset, it has been a very long time since I have enjoyed an event as much as this one. The "feel" is visceral. I don't know how else to define it
On flat ground and moderate inclines I could maintain posted speed limits. On steeper inclines I grabbed lower gears as my speed declined. In all but the steepest climbs I was able to crest in 3rd gear at around 45 miles per hour.
I just got back from the Solid Axle Summit in Ouray Colorado. I pulled this ~3,400 pound trailer through Utah and Colorado mountain passes for 640 round trip miles. I averaged 17.4 miles per gallon. Combined GVW for truck and trailer is ~9,000 pounds.
I climbed Davis Pass in low range 2nd and...