Hi and welcome to the site! I'm pretty new myself. Don't have any info for you on where to get the three point parts, but do have some info on the axle seal leak. Seems to be a common problem and that's what brought me to the site not too long ago. Here's a link to a recent topic addressing the axle seal leak on my 4410, there is a link to a webpage I made with some more pics and info within the thread.
Recent Axle Seal Leak Thread
Its a very easy job.... if you have a press to get the parts apart and back together again.
__________________
JD 4410 CUT - 420 FEL, LX6 Rotary Cutter, Frontier 6' Rear Blade, Frontier SB1106 Sickle Bar Mower, i-Match
JD X740 - A Beast of a Lawnmower!
www.thejonesfarm.com