Bought my one owner 97 two months ago with 120,000 on it and the tranny fluid was black! Car had lots of service records from the dealership, but none with a tranny fluid change. My buddy is a mechanic and they do the flush with the machine. He recommends that, rather than dropping the pan on an older high mileage car that hasnt been serviced regularly. Less contamination, better job cleaning. Says clean, fresh fluid will not damage your tranny. The damage is already done, if there is damage. I had him do mine and I've put about 1000 miles on it since, smooth shifts...no slips. So far, so good.
Also had him do a coolant flush, which was black. Since, Ive changed P.S. fluid, brake fluid, front & rear struts, stabilizer bar bushings. plugs & valve cover gasket. A little more money and I'll have a new one!!!!