Manufacturers recommend a ATF flush every 100K miles because their maintenance schedule is calibrated for a 100K lifetime for the car.
To get your car to last 200K or more, you need to do the routine fluid changes far more often than the dealer recommends. The standard for a tranny flush is 2yrs / 30K miles.
However, before you do it - pull your tranny dipstick and inhale deeply. If it smells burnt you are probably already screwed, and a tranny flush could finish off your transmission by loosing up the sludge that is holding it all together. If that is the case, you might just want to drive it until it dies, and deal with the $2000 rebuild then. If the fluid smells ok - and still shows sign of its original pink color, then a flush is in order ASAP.How much is it for a transmission oil change on a S-10?
between 30-50 if u doit ur self and 100-150 if u take it somewhere i would just reccomend a feliter kit which u remove the pan and replace the filter and just replace the fuild loss usaly 6-10 quarts a flush can harm the tranny if it has never been flushed befor 75000