As far as I can see all those codes that you have posted come up as shift silinoids preformance/stuck

If you havent already get rid of the Edge tunner and pray you dont need a new tranny

SCT tunners are the only way to go for the 6.0

P0751
P0756
P0761
P0766

P0751 Shift Solenoid "A" Performance/Stuck Off G*

P0756 Shift Solenoid "B" Performance/Stuck Off

P0761 Shift Solenoid "C" Performance/Stuck Off

P0766 Shift Solenoid "D" Performance/Stuck Off

I dont know if you will just be able to replace all the shift silinoids or what

First thing that I would do is remove the edge tunner and see if that helps

then read thru this it may help your problem

https://www.ford-trucks.com/forums/8...eshooting.html

and this one too

https://www.ford-trucks.com/forums/8...-strategy.html

there were a couple more PDFs on tranney assembly/disassembly I couldnt find them in the tech folder so PM me your email if you want and I will send them to you
they were helpful and had pics of the shift silinoids and stuff




Definatly ccheck for shift lever Binding although dont know if it will help since the shift silinoid is electronic but couldnt hurt