axle problem

well i've been having a problem when i step on the gas on my dc gsr....the steering shakes....i thought it was my axle so i took off my axle and the driver axle outer shaft had no play....it would get stiff in one place until i slam it into the ground.....also how the hell do you seperate the half shaft?.....i remember i use to know how to do it.....this one just won't come off.....need input thanks