Hi, sorry, I never followed up with the actual part numbers I replaced on my 2002 4115. These may be similar for your 4110, but I would double check with your dealer. I ended up replacing the upper bearing #10 M807422, upper bushing #12 LVU800629, the shim #16 M808574, the seal #22 CH14665, the sleeve #23 M807497, the lower bearing #25 LVU800252, and then finally the actual pinion drive gear itself on one side #13 LVU803535 (it was pretty chewed up). All in all this was about $300 worth of parts. You will learn more once you get in there and dig around, but effectively I had worn bushings and bearings that created lots of slop between the vertical pinion gear and the final drive ring gear, and this caused the seals to fail and one side's pinion to be damaged. It started out as a small leak but got much worse pretty quickly.
Hopefully you are able to get the parts you need, in the correct sizes to your existing pinion and housing setup. From what I understand, there is some point in which John Deere updated the design and made the pinion, bearings, and bushings larger, which required a new upper housing (#14 GEAR CASE), and also maybe even a new lower housing with a larger bearing (#26 GEAR CASE). Our dealer was nice enough to order the parts and let me do some fit checking with my old parts before he charged me. Good luck!
Hopefully you are able to get the parts you need, in the correct sizes to your existing pinion and housing setup. From what I understand, there is some point in which John Deere updated the design and made the pinion, bearings, and bushings larger, which required a new upper housing (#14 GEAR CASE), and also maybe even a new lower housing with a larger bearing (#26 GEAR CASE). Our dealer was nice enough to order the parts and let me do some fit checking with my old parts before he charged me. Good luck!