need answers before I sell

ok, I have a 1984 silverado 3/4 ton 4x4 with a goodwrench rebuilt 6.2 so I know that is good, starts quick, runs great. but it has a turbo 400 which im not so sure of. I owned the truck for quite a while, drove it all the time, it drove and shifted perfect for along time, but eventually the fluid got dark and dirty and I didnt clean it right away and i guess the filter got clogged and then I towed a car home on a dolley, and then on my way bachk from returning the dolley, it started not shifting to 3rd, not engaging to first until a few seconds later, then I had to stop to not hit a car in front of me and when i went to take off it wouldnt go, it was like I had a centrifigul lutch, now i know this wasnt the smartet thing tpo do but i had to get home and had no money to get a tow truck so i jiust revved it and eventually I was going, also for the 10 minutes prior I was doing 10 cuz it wouldnt leave 1st.

I got it home, let it sit, and bougtht a tranny filter kit, and fluid. now a month went by and I difdnt change fluids, and I started it and it went into 1st and to revers but like a 2-3 second delay, and it shifted normal though, so I figured the stuff settled in the filter and pan so it was getting fluid again, went back, changed filter and fluid and now it is driving perfect, shifts just liuke it should. the thing that worries me is when i took the pan off it was like mining for silver! lots of metal flakes in there. the fluid is staying clean now though and no flakes on dipstick when i pull it out.

but Im selling the truck and a guy I worked with wants to buy it but I dont know if I wanna sell it to him.

you think the flakes were just cuz of when the fluid wasnt flowing good and i used it like a centrifugal clutch ands now with fresh fluids it is fine and I should sell it to him, or is it gonna happen again soon and dont screw a friend?

thanks