You have to pull the trans. pan, renove the shift annd throttle linkages and then remove the valve body, push the old seal out the top. I have used a socket that is just larger than the hole where the seal fits to pull the new seal into place, there is also a small seal on the throttle shaft but I think you can just remove a "c" ring and pop it out and put a new one in. By the way, the seal usually only leaks if the truck has been idle for some time, might not be worth the effort if it's not too bad. bg