I've only put my 3pt hitch on a couple of times, but I don't remember having the difficulty you are having. Once you get the check plate on, the lower link pin shouldn't come out. Seems like I may have loosened off on both turnbuckles of the check chain assy to make installing the check plate easier .... dunno for sure it's been a while.... now you've got me wondering 
Never thought of that. Definitely a good place to store those bushings.
Hotwheels said:Tex - i like your storage setup. I just put the bushings on the cleavis pins in the tops of the lifting rods - how I got it from the dealer. That did cause me a little trouble the very first time I went to connect the lower link pin 'cause I didn't realize they were there....
Never thought of that. Definitely a good place to store those bushings.