Yes the do have something in common. They're in the same box,lol.
When reverse is selected,almost all the other circuits are locked out, and the line pressure rises to whatever the pump can put out. Only the TC is charged,and the L/R band & hi-drum, are engaged.
Hey I think I see it, If the KD servo has failed, as in a oil pressure is passing through it or around it, this will force the band to release, and the pressure will feed into the direct clutch. That's the half of it, now how to apply the L/R band?
Got it! If for whatever reason the 1-2 shift valve fails to move (be it; the governor fails to command it, or the valve is stuck, or the wrong spring is on it),then the L/R band will be energized just as if manual low was selected. Since the L/R band is used in both low, and reverse, it's being stuck on would go un-noticed, even in neutral, cuz the other clutches involved are dumped in both neutral and park.
So, I mighta bin wrong in an earlier post. The issue could in fact be hydraulic. It's just a little hard to imagine. At least for me...
I know it's a long shot to have 2 errors in a rebuild, but if the shoe fits.