I bought my car with 51,000 miles on it 2 years ago. I had the tranny flushed right after I got it and then just recently when it had 71,000 miles. The machine that was used on mine does not actually do any pumping. The machine is filled with new fluid then it is hooked up to the fluid lines going from the tranny to the radiator and coming from the radiator going back to the tranny. The car is started, it just idles in park and the transmission itself pumps the new fluid in from the machine through the line that comes from the radiator and the old fluid back into the machine through the line going to the radiator. There is a window showing the fluid coming from the tranny. When this window shows new clean fluid the job is done. The lines are hooked back up to the radiator and you are good to go. With system there is now way to harm the tranny because it is just like the tranny pumping the fluid to and from the radiator to be cooled.
