Transmission slipping

I learned this from my own experience with rebuilt valve bodies sold on E-bay. The say there refurbished/rebuilt. But what they really are is junk yard valve bodies that they take apart clean and ohms test the actuators. So you can see how it could work good for a little while then not work so good. What happens to the valve bodies is the pressure regulator is constantly moving in the bore. Which the bore is part of the upper valve body where the actuators are. The true to fix the problem of unstable line pressure too high or too low. Is to get one that has had the Sonnax repair kit done too it. I actually did my own Sonnax repair I bored the regulator bore installed the sleeve put in the Sonnax pressure regulator and spring and Sonnax boost valve. The transmission shifts better then they did new I have driven hundreds of new Saturn's. The only way to truly check how your valve body is working is with a transmission pressure gauge set and a scan tool that can perform a step pressure test on the car. You could do a high/low pressure test with just the transmission pressure gauge set but that does not always tell you right away. Sometimes if it is bad enough I can tell just from that. Do you have any codes in the computer? Or a delay bang into reverse?