I'd change the fluids if your wheeling style includes a lot of water crossings, or your terrain is exceptionally dusty. I've alway been a little leery about tranny flushing. If the fluid is clear red with no "burnt smell" and no cloudiness, I'd just do a drain/fill/drain/fill cycle, cleaning the filter screen on the first pass, and retorque the valve body bolts. The only way I know to "flush" the power steering (and I use the same criteria for changing this fluid) is to remove the return hose from the reservoir and put it in a waste container and add fluid as the old pumps out, making sure you don't get any air into the system. I've never changed my power steering fluid, and it's still clear as new - probably only added less than 1/2 can since I got the truck, a tiny dribble at a time.