JD does have a special blue grease that they use between the sealed ball bearings and the triple lip seal. While using this grease rather than just any gun grease may help somewhat, the facts are that in this application JD has the seal running on a STEEL ring rather than the nylon ring and no matter what grease you use it is going to get dirt in it, especially in some dry soil seeding conditions.

This seal works best when running on a nylon ring, not steel, and when you can occasionally purge grease past the seal as it was designed to do.

You can go to the blue grease but I would not expect very large increases in seal life due to the fact it's running on steel and not purgeable, if that is a word. jmho. A lot does depend on your soils. Seal life and resulting bearing life in dry, abrasive Texas conditions is much less than in moist Ohio River Valley conditions.

Jim at Dawn