F150online Forums - Tranny Question???

you will have to excuse my questions I am a new ford owner only owed chevys in the past and now have a yard full of fords. My 2005 lariat f150 has 127k miles and is starting to shift hard and make a clunking noise when it shifts down from overdrive when I accelerate, anyone have any ideas? I don't even know what tranny I have, I would like to know what can be done to ford trannies to beef them up, I used to put corvette servos in all of my chevys to beef them up is there anythng like that for my Ford?