[911monty]

Luv2box; There are several trans flush systems out there that use pumps to flush the trans. Some attach directly to the filter pick up tube and pump through the trans. They do a good job of removing the old fluid.
Unfortunately auto trans have very complex valve bodies that control fluid flow and pressure which controls shift points. There are also clutch packs for EACH gear. These clutches are very thin and are the source for a lot of the debris circulating within the transmission. A cause of failure on a long neglected trans is the removal of The friction material circulating in the fluid. This material helps keep the clutches from slipping. When it is removed the clutches can begin to slip in the clean fluid and then the trans will fail. More than a few well meaning car guys have serviced the trans only to have it fail.
Change your auto trans fluid regularly and it will last much longer. I have a BMW with lifetime trans fluid. I change it regularly. Drop the pan, change the filter, add 4 qts. Remember they also recommend 10k oil changes.

PS. I mentioned the valve body earlier. The only way to clean is to use a system such as JFP mentions, that moves fluid through the entire trans.