I just recently changed mine using this great technique. After I flushed out maybe 4-5 quarts this way, I simply kept adding 1qt fresh fluid through the dipstick tube, and running the engine just long enough to push out 1qt of old fluid. This keeps it from running dry during the flush. Repeat until clean-ish looking fluid comes out of the return line. I ran through about 14 quarts total.

My old fluid was as black as dirty motor oil and I would be willing to bet it had never been changed in all the 184k miles. I also went through the trouble of dropping the pan and changing the filter, but it was so clean inside the pan that I kind of regret doing all that extra work. Definitely use the genuine Mitsubishi Diamond SPIII fluid. It shifts beautifully now - no problems at all since the change. <img src="/forums/images/graemlins/kewl.gif" alt="" />