I flushed the PS system on my old IROC Camaro by disconnecting the return line to the pump and letting it flow into a drain pan, and keeping the pump reservoir full, and just let it pump the new stuff in until the return line ran clear. I know the thing calls for Dex3, but instead I used a 50/50 mix of Valvoline Maxlife PS fluid and Valvoline Synpower PS fluid. That was a couple years ago. Still works just fine.