Pulling the wheel,hub,drum assembly off is not that hard a job and there will not be a great deal of oil leakage. Jacking one side up will tip the housing and the oil will run to the other side. Pull the axle shaft and removed the nuts holding the bearing in place. Put a fabricated dolly under the dual tire assembly and pull the wheels, hub and drum assembly off as a unit on the dolly. The jack under the axle will allow vertical adjustment so the dolly takes just the weight of the wheel assembly. No need to take the wheels or drum off the hub.
I fabricated a dolly with 4 large casters and 2x4s, about 2 feet square and to hold the tires about 1 inch off the deck. You need a hard surface to work on. If you have a smooth concrete floor, a sheet metal skid can be placed under the assembly in place of the dolly and the floor greased to allow things to slide smoothly.
Caution must be used that the truck is blocked up properly while the jack is in use adjusting the height.
The wheel assembly can be removed with just the 6 or so axle retaining bolts and two bearing nuts in about 10 minutes, not counting fabbing the dolly. Still some heavy work but I have done it by myself.
A pallet jack can also be used in place of the dolly by inserting it under with the tires between the legs of the jack.
