When I got my 83 SD in may of this year [2003] I really had no idea what to do first, it needed so much work that I did the easy things first. One was flushing the tranny. I un- hooked the return line to rad on driver side and placed the line in a 5 gallon pail. I then started car and with the fliud going into the bucket I began adding new fluid as fast as the filler would take it with out overflowing. The fluid was dark, not real dark, like black, but sort of brown. After the fluid began to feel cool, about 4 gallons in the pail, I figured the flush was complete. I topped it of and went for a drive. It shifted much smoother than before the flush. To make a long story short I just finished flushing my tranny for the forth time and it gets smoother and smoother every time. The question is: Am I nuts? or can flushing a tranny with 230,xxx miles keep getting better and better. The 4 flushes were over a 7 month period. any and all comments welcomed. steve