Question about tranny flushing technique

[eakins]

called my local independent toyota shop about flushing tranny.
they said they just unhook the cooler lines & remove the drain plug to flush a tranny.
is this correct?
others here have mentioned they gone to place that used equipment that literally pumped the fluid out.
that's the deal? thanks!

[toyomoho]

A trans has 4 or more quarts of fluid the majority in torque converter; this fluid cannot be drained out on most trans. A flush would be considered pumping out all the old fluid into a container while drawing in new. There are a couple of types of flush machines, the best requires removing the pan to allow the trans to draw in the fluid.

It is possible to drain and refill the trans pan, then remove the cooler line going back to the pan. Start the engine and allow the fluid to run into a container, when the fluid runs out stop the engine. Repeat this process a few times and clean fluid will start to appear.