I just wanted to add that I charge my tranny fluid & filter every 30k miles, and use Redline Synthetic ATF. My '88 TE has 176k miles on it, and shifts the same as it did when I bought it at 67k.
"If everything seems under control, you're simply not going fast enough" --Mario Andretti
1995 E500 street car
1986 Porsche 944 Turbo S track car