BRIAN - I wouldn't call the rear wheel seals "Trouble-Free", they do wear out and leak. Not sure I'd replace them until they start leaking. They will weep a little, wet the back side of the wheel flange with oil long before they drip Hy-Tran on the floor.
On a hydro, ALL CC's used needle roller bearings, and those I would call trouble-free. The earlier GD's in the low HP tractors, 70, 71,72, etc used a plain bronze bushing and those did wear. "Past tense" because I swapped the axle carriers on my 72 with the ones from a 123 chassis I have.
What's funny is when you buy your rear wheel seals from an old Cub Cadet dealer that's also a Case/IH or now Case New Holland dealer, the ticket with the parts calls the rear axle seals a, "Corn Head Gearbox seal".
JOHN B. - International, or Navistar has a gray sealant they sell in a small tube or chalking gun cartridge that's supposed to be REALLY good too. similar to Right Stuff, only better. Not sure what they call it either, or have a part number but I could check on another forum and see if I can come up with a name & number. I know my local C/IH dealer has it on the shelf. Not sure about the 300 & 400 series engines but I know the old 7.3L PSD's, and T444E's used that sealant on the oil pans, never heard of one leaking at the pan to block seal, but the dip stick adapter that's sealed with an o-ring almost always leaks.