545rfe filter and trans fluid

Changing five quarts of fluid in a system that holds what eleven really isn't going to clean anything or improve anything except to replace some of the seal softening and friction protection additives. If you really want to get a lot of old fluid out and there's no converter drain plug, then loosen the valve body bolts and the converter will drain down over halfway. But if the fluid is clean and there's nothing in the pan, it's all really a waste of money when you could just dump in a bit of trans additive. If there is any debris and the fluid is dirty, then the trans is worn, and the next phase is particles clogging the filter and loss of pressure; which is the real enemy of a trans. I usually change the filter and dump the same fluid back in; with some additive. These shops that change the fluid without changing the filter are doing a huge disservice.