How do i change the trans fliud filter and flush the system out?

It's a messy job but, jack the car up on jack stands as high as it will go. Be sure it is safely on the stands by shaking the car after it is on them. remove the trans bolts starting at the lowest end one at a time. slowly work your way around by ONLY loosing each bolt a turn or so. It will start to leak fluid a little at a time. As it slows or stops loosen more of the bolts one at a time. When you get to the last one or two bolts hold the pan up with your hands and remove the bolts slowly, do not let the pan tip there is a whole lot more of fluid yet and you need to tip it. The filter is more than likely bolted with one or two bolts. after being removed wiggle the filter and pull down, More fluid will come out. It no bolts possible clip, same thing just wiggle after removed. Older cars should not have the trans FLUSHED it will cause trouble with the seals and o-rings, just install new filter and gasket tighten bolts in a cross pattern (side to side)then refill trans check for leaks before starting. check again after starting then fill to correct level.