I don’t see what the issue is. Swap the connector and be done?
As for Gear Vendors, why would he try to talk you out of giving him profit?
You’re adding weight, rotational mass, and drag. You’re hyper focused on RPM. There’s a reason the transmission has the final gear it does. If it could pull a substantially deeper gear, I guarantee Ford would have used it for their fleet MPG number.
I don’t see where the free energy is going to come from. I think you’d have to substantially lower the truck, and add some low rpm torque or you’re just going to be chasing your tail.
I see that I did not answer your questions directly:
Q) As for Gear Vendors, why would he try to talk you out of giving him profit?
A) I figure two reasons, one it is a complex fitting job, and if he is right about a conflict with the rear end VSS and the transmission's OSS then he has no fix.
Also he said he does not work on newer cars.
Q) You’re adding weight, rotational mass, and drag.
A) Weight yes, but not even the same as one adult...do you feel having another person aboard cuts YOUR mpg badly??
B) Rotational mass: a little but I believe it will be off set by the gains.
A) Drag, as in wind it will be tucked up behind the main transmission,,,so no drag.
Q) You’re hyper focused on RPM. Yes that I did answer...
Q) There’s a reason the transmission has the final gear it does. If it could pull a substantially deeper gear, I guarantee Ford would have used it for their fleet MPG number.
A) No they put gears in for performance, this is a little truck made as a SUV, so the gearing is for best OVERALL performance, rock climbing, and towing, after all it comes with a trailer hitch and plug, my god she is one fast little truck, the hot rodder in me LOVES how she JUMPS off the line...the smart guy in me thinks those 373s are NOT needed to get her off the line, in fact she will take off mildly in second and third with no fuss.
Overdrive ratios are going lower: the 5r55 OD is .71 and the OD in a 6R80 is .69, and 8R80 is .65 and in a 10R80 it is .64
I had a 56 Studebaker Golden Hawk in 1965 and raced Mustangs on the streets, this was a 10 year old car, with a heavy full frame and heavier thicker sheet metal body and yet I could beat them across the Intersections but they would over take me as I had to shift to second as my Studebaker 289 would not run over 5K...
I beat them because my Studebaker had a even taller rear end around 411 or higher stock...it was usable as it had a 3 speed with overdrive.
In 4th it was running at around 3K at 65/70MPH....but NO ONE cared about MPG then.
I also have a 68 VW BUG a 1600 (1.6L) engine a 4 speed stick shift trany, NO water pump, no power steering, no A/C, That SHOULD get 60MPG...but it does not it is lucky to get 25MPG at 65/70MPH because of its gearing...
My wife's 2000 Toyota with all the bad stuff a bigger engine, A/C, power everything, automatic gets 35+ MPG at 65/70MPH....