Correct transmission fluid level - not as easy as it sounds.
The manual calls for checking hot, but not after driving for long periods at high speed, or idling with air conditioning on in hot weather. In these cases wait 30 minutes. Fluid temperature should be between 158 - 176*F, and level between hot marks on dipstick. That is, not above the "dip" center of the upper mark. Then the manual has a note in bold capital letters: "Do Not Overfill." I thought I'd been doing this right but I actually had filled slightly over the top of the top mark. (the part where the "dip" ends) Drove the car for 9 miles one evening and the fluid level was between the "hot" marks. Then checked it after a longer freeway drive and was above the top mark. So let it cool awhile, placed an oven thermometer on the case and it read 165*F, so I siphoned off a bit of fluid to get it just at or slightly below the "dip" center of the upper mark. Surprise. The car seems to run better now. There was always an unidentifiable whine in the transmission which I'd thought was normal - now gone, plus it seems to idle more smoothly. Perhaps just my imagination, or perhaps they actually have a good reason for saying "do not overfill." If it took me this much effort (I usually add back in the same amount drained by measuring in the graduated empty quart oil containers), imagine how likely it is that the quick lube place gets it right first try.