So, I just got my 1982 Chevy K10 started today, and went for a drive. however, when i shifted the transmission to Drive(overdrive) the trans does nothing, it does not attempt to move the truck. same for 3rd gear. however, if i place the transmission in 1st or second, the truck drives fine. Here is where things get odd. Once i get moving, i can shift into overdrive, and the transmission will automatically shift through all gears as they should. However, if i shift out of overdrive, ( into neutral/reverse/park) i then have to shift back into first, take off, and shift up into overdrive. I was hoping someone had seen this or had any ideas as to what the cause could be. I have attached the current tune in the truck.