Tractors and loaders often have specific "grease points" (zerk fittings) that require heavy-duty polyurea or lithium complex grease to handle rugged terrain. Maintenance 101: How to Grease Your Axle
Grease acts as a seal, shielding delicate bearings from road salt, dirt, and water. axle grease
Often use marine-grade grease or high-temp lithium to handle the heavy loads and potential water submersion. Tractors and loaders often have specific "grease points"