2001 Silverado 1500 Tranny drain and replace quart capacity

[wazzabie]

On a 2001 silverado 1500 with a 4L60E tranny w/ deap pan and drain plug -- I pulled the plug and measured 3.5 quarts of fluid that came out. The factory Helm shop manual for the 01 says 5 quarts.

Any thoughts on how many quarts for just a drain? I'm not dropping the pan as the filter was changed recently.