Somebody told me one can drain more fluid during an automatic transmission drop-the-pan fluid change if the transmission is set in reverse. Any truth to this?
What that someone may have been thinking of is once you have begun to refill the transmission, you should shift the transmission through the gears while hot, and then measure fluid level to determine how much fluid is needed to top-off.
Shifting through the gears insures that air is purged from the system and that each acutator piston becomes pressurized.
That's the method I use, and I've posted that method many times on this site. Not all my friends are that sophisticated or willing to do the fluid exchange procedure.