Honda Repair: Honda Automatic Trans flush procedure, atf cooler, automatic transaxle

Question
My question pertains to flushing an Automatic Trans to get BOTH the sump fluid changed AND the torque converter's fluid changed.
Part 1 or 3:     I ask you opinion on the best way to do your own automatic trans fluid flush on Honda 1997 CR-V 9with 4 speed automatic transaxle).  There is no external trans fluid filter, nor is there an internal filter to change.  I have removed the ATF cooler "return" line from the heat exchanger allow me to route the outflow of ATF into my drain pan) going back to the transaxle,(I actually attach a 3/8" id rubber hose to the heat exchanger fitting and route that hose to my drain pan.)and captured the outflow in 2 quart increments when the eingine is running at idle RPM in neutral gear.  It takes about 25 seconds at engine idle speed for 2 quts of "old" ATF to be pumped out into my drain pan.  Then I stop the engine and add 2 more qts of Honda ATFz-1 fluid to the transmission case and again start the engine to idle for another 25 seconds, again getting about 2 qts of ATF captured in my drain pan.  This process of "idle in neutral/capture outflow/stop engine/refill trans" is repeated until about five of these "2 qt flushes" are completed and then I re-attach the cooler return line (from which io've been getting the "old fluid" and  top off the trans level.   I've settled on 2 qt increments to be sure i never dompletely drain the trans sump in the process and cause the pump to starve for fluid - the sump holds 3 qts, so 2 seemed to be a good amount to stop at.   I've been told this process allows the internal trans pump to exchange fluid inside the trans case and torque converter, so BOTH the ATF in the trans sump (about 3 qts) AND the ATF in the torque converter (approx 4.5 qts) gets flushed and exchanged thanks to the pump in the transmission doing the "internal flushing and exchange" of fluid.  HOWEVER, I am not a trans expert so I don't know if the exchange of ATF within the trans really works that quickly and evffectively with this procedure because the transmission is not shifted through the various gesrs during the porcess, and I do not know if the internal trans pump circulates fluid between the sump and torque converter at an idle RPM in neutral.
Part 2 of 3:     An alternate flush technique was told tome by a Honda dealership mechanic.  He says to drain the sump (3 qts) and replace with 3 qts of new Honda ATFz1, then run the engine at idle shifting the trans through all gears for 2 to 3 minutes.  Then stop the engine and drain out the sump (3 qts), refill with another 3 qts and again start engine and run trans thru the gears at an idle for 2-3 minutes, and continue this until at least 6 qts, preferably 9 or 12 qts, have been drained/flushed and verify the fluid being drained out is very clean (visual check).  He says this is the official Honda maintenance manual procedure and that Honda does not officialy endorse use of external flushing machines such as you see being used at quick oil change shops.

Part 3 of 3:     From you experience, which is a better way to flush as a do-it-yourself-mechanic-at-home?  ALSO especially, with the 1st technique (return cooler line removed to capture the fluid being circulated through the heat exchanger in the radiator) is the internal trans pump really exchanging fluid between the sump and torque converter if the trans is always in neutral at idle RPM.
I'll appreciate any experience you have.

Answer
Hi Ralph, there is no real way to 100 replace all fluid in the transmission. But, by doing the techniques you are describing you should achieve 85 to 90 of the fluid replacement. Which is fine. Some transmission shops have specific tools that mount to the transmission and either feature hi-pressure or vacuum to replace fluids. But these are expensive to purchase and not practical for the home mechanic. Your advice that you received wasn't exact nor wrong. Remove the transmission lines to the radiator and use that technique is what i would suggest. But i would not recommend going through the gears on 3 quarts of fluid. This can be dangerous and expensive. Engine idle is all that i would suggest. If the fluid levels are low the torque converter will fill first due to pressure wanting to be built up. I hope this helps...