Looking at your 3rd picture. Slide the bronze cup off the shaft and you'll see the 2 flat rubber packings (seals). They're still available from Deere for about $5.00 each. Part# A668R. New ones look like large garden hose washers.
Inspect the front face of the cup. It should have a nice flat machined surface. It rides against a bronze bushing that should also have the same type of surface as the cup. The part# for the bushing is A621R. It's available from Deere for about $19.00.
The flat packings AND the cup & bushing work together to keep the Powr-Trol oil in the Powr-Trol sump.