On my old 99 Sierra 4.3 I used to change the transmission fluid by removing the out tube at the rad and start the truck. It would then pump the fluid into a bucket. I would stop doing this when the pump went wooosh, wooosh a couple times meaning the pan was empty. Then I would fill the pan up. Then start the truck and repeat a few times until I felt I had removed most of the fluid. It was good enough for me. Think this would work on a 2010 Sierra 5.3 - 6 speed? I didn't want to change the filter.
Thanks
Jim