I have run the KO2 in the past and currently running the Yokohama MT. Both are E rated tires, it is possible to find D rated tires in that size but most are E.
The top tire companies like Toyo, Yokohama, Cooper, Nitto etc are all E rated.
The Milestar Patagonia, Kumho are D rated. Not a lot...
Great work @OlafLX wiring can be daunting especially knowing you could fry something or yourself if done wrong.
When I wired in my second battery I studied this schematic several times and had it taped to the hood of the LC while I did the work.
Honestly might not be a related issue hood and shifting out of park. I would check the brake switch on/near the brake pedal and make sure it is still good.
Where in AZ are you located? If you are in the Tempe/Mesa area I would talk to @Cruiserhiggs or @richardlillard1 both do great work and can get you back on the road.
Don't see the year of your rig but you might have the smaller/thinner drive flanges. Might want to upgrade to the latter model ones and you might not have that issue.