My truck is poping everytime i stop and start and now its doin it when the tranny shifts. I climb under it and notice that the yoke comming out of i guess the transfer case moves when i push on it and sounds like theres gears poping on the inside. It moves about the thickness of a quarter. What the heck is wrong ?????

That is too much play. There is a babbit bushing( some are brass) in the tail section of the transfer case where the driveshaft yoke goe in. Generaly you only want enough play there so a slight film of atf can get in and lubricate spinning yoke (20 thousands max). I suggest you get it checked out asap before you hurt anything .

mike