A friend has a car that has leaked transmission fluid for some time. I spoke with a transmission shop who said to not flush/exchange the fluid because it might break up the metal particles and cause a shift malfunction. They also shop said to just change the fluid and filter and keep driving but to NOT flush/fluid exchange. I've looked into the BG transmission fluid exchange machine and wondered if I was given good advice or if a total fluid flush/exchange would be best for a tired transmission. Any ideas?