If he had drained the pan (~3.5 qt out of the 8), refilled, d/c the line (and direct into a bucket) - he could have achieved better and faster results with 9-10 qt of fluid instead of 16. His method took significantly longer, wasted more fluid and probably resulted in worse results since the clean fluid mixed with the dirty fluid that was in the pan.
There is no way that his method would have removed/mostly diluted all of the "cleaner" that was mixed into the system. That P/S fluid exchange was just a painful exercise to watch. Emptying/refilling the reservoir a few times would have probably delivered comparable (and safer) results.
I have a few 4t65e GM transmissions I service. First I will say that I'm NOT a mechanic for a living; if I tried, I would probably starve to death or be fired because I don't TRY to be fast. They're MY cars and I TRY to be thorough. I drain the pan and then change filters (~7.4 quarts), then refill the pan w/clean fluid, then (with the E brake set, rear wheels BOTH choked in both directions, front jacked & supported), I disconnect the cooler return line, jam a clear hose extension on it and aim for a clean, empty bucket. Start the car. (No load at all on FWD), put it in gear, GENTLY, actually, manually, go thru the gears including reverse, until red fluid comes out the hose. USE THE BRAKE, STOP WHEELS FROM SPINNING. Put the car back in Park, shut it down. Reconnect cooler line. Set it down on level ground, refill transmission to ~1 qt LESS than what drained out. Restart car and let it warm up. Check trans. fluid and top as necessary. Car now has as nearly a complete trans. fluid change as is possible (including valve body) without removing trans. from car.
PS fluid change can be done simultaneously with car in air. Disconnect return line to pump; drain it into container with extension hose & barb shoved on it. Put vacuum cap over hole on bottom of reservoir; refill reservoir. Leaving engine OFF, but front wheels in air, turn the wheel lock to lock until clean fluid comes out the return line, NO LOAD on system. Reconnect line to pump, refill pump, again turn wheel lock to lock several times. Top off as necessary. By the time the vehicle is started, there is no pump "whine" and very little air in system; and I've used ~24 oz. of fluid on a system where manual says capacity is ~16 oz.
One man pressurized brake bleeding is made easy with Motive power bleeder and speed bleeders, and I DON'T dump fluid all over.
When I'm done with everything, you can walk barefoot around on the garage floor and then step into the house without leaving dirty footprints on the floor.
Most everything I do I have gained the knowledge and methods from guys like you, Trav, Clinebarger and several other very knowledgeable posters on this forum whose IDs fail me at the moment. I owe BITOG an unpayable debt of gratitude for this experience.
In the real world, I am a Quality Control manager in a welding shop; I'm not even sure I like working on cars at all, including my own. I do it because, in the past, I've patronized shops in my area, including two car dealerships within a few miles from me, and they make my stomach turn. I would not take them my kid's little red wagon. They have EARNED the BITOG tag "Stealerships." Sloppiness, carelessness, outright dishonesty, complete and total lack of respect for customers or even themselves. I'll stop the rant.
If I could find someone such as yourself anywhere near where I live, I would be a regular patron and buy you occasional beer & pizza just to let you know I appreciate what you folks do.
