Metal in the pan, shifts good, fluid great any guesses before I pull it down?

Did you use the TransGo TF3 manual kit? If it is, the throttle valve linkage and it's proper adjustment is just as critical as it is on a LoadFlite equipped tow truck. The rule of thumb Go/No Go gauge for a three speed automatic is somewhere around a level table spoon full of wear material debris in the bottom of the pan after everything settles out. Is there a magnet in the pan to catch ferrous debris? Those shavings look more like bushing and drum material than steel and clutch pack, which would coincide with the fluid not being outright scorched black.