my guess is that the shaft was not in alignment to engage and could not be moved with the hog attached.. with the hog not attached.. you coul move it.
remember when i aked you to do this very test? IE.. rotate the pto shaft and try to engage it.
i seem to remember you said you did and it wouldn't.
and yet now it does?
int he end.. if you have 3/8" of thrust play.. .. you need to fix it. they don't heal. and you can get more damage...