how long since last tranny serivec and how many miles on the truck
?
the oem solonoid will suck up small particles and cause the probs you are taling about, then wil cause the bands to fail, I would do the gm swap and fluid and filter flush, now get it flushed, there is a difference if hyou dont flush it, the prob will just come back, those particles of cluthc are in the cooler also