The lines are great. The video is fair. Left out some stuff that matters. You only take off one cooler fitting at the radiator at a time and put on the new fitting. The cooler is loose in the tank. If you take off both it will fall down in the tank and you will lose the coolant in the radiator. Also don't get the fittings too tight. Snug them up with the nut above the o-ring. Also, you will need to cut the lines in 3 or 4 pieces to get them out. No room otherwise.
Duramax trans cooler lines