Subject: trans
Question: My Ford has 120,000 miles of which every 50,000 I get a transmission filter replacement. However, I have not gotten a total flush through as they are so expensive. I have heard that just getting the filter changed still leaves the torgue converter full of dirty fluid. Is a total flush dangerous to the trans? and is it worthwhile? I have heard there are several different methods to do this, some of which appear to just recirculate dirty fluide back into the trans. What is your opinion on this. Thanks. Larry. Quincy, CA
Answer: Larry,
I don't know too much about Fords, but your question is pretty universal. True, when you just drain your tranny fluid, there more than likely is dirty oil left on the torque converter and other areas of the transmission.

The thing about ATF is that is a detergant. The tranny fluid itself will clean tranny components. And any dirty fluid left in the transmission after draining shouldn't cause an problems. Also, the new filter you install will help clean out any large particles that might have remained in the torque converter.

If you do want to try for a more thorough flush, find youself an air compressor and you can force out further fluid with compressed air. But that shouldn't really be necessary unless you're really gung ho about getting out every last drop of fluid.
Good luck!