Front Drive Shaft

[remercroft]

after i got my tranny serviced i started hearing a clanking sound from under my seat. u can hear it best at low speeds. i crawled under the truck and started wiggling my front drive shaft. the slip yoke moved and the faster i shook it the more it sounded like the clanking noise. so i found my problem. now comes the lack of knowledge. is it slipping because a u-joint is bad or is the yoke bad. do i have to buy and replace the yoke or is the drive shaft one piece. hope not that shaft is expensive. thanks. oh yea, has anyone ever wondered why something else goes wrong shortly after you fix one thing. thanks.