I'm not sure about the Tracker but most auto trannys are sealed and do not have drain plugs like manuals. This is true for the 420A autos.

You can drop the pan and drain it that way but you only get about 3-4 quarts that way. The rest would still be in the torque converter. This way is messy and you will need to replace the gasket and make sure all bolts are torqued properly to not have any leaks. If you do step and repeat this process over a series of 3-4 days, you will have replaced at least 90 percent of the fluid. While you are in there, you should replace the filter and clean the magnet.

The only way I know of flushing it is taking it to Satan or a Jiffy Lube and have them do a automatic transmission flush. They say that will replace 100% of the fluid.