Place the rototiller on a flat surface and detach the spark plug wire to ensure against accidental start-up.
Push the engine compartment onto a sturdy wooden block so that the wheels are no longer touching the ground. Troy-Bilt recommends putting the block under the transmission.
Loosen the hex bolt and lock nut that holds the wheel to the wheel shaft. Remove the wheel. Repeat this process for the other wheel.
Clean away debris from the wheel shaft with a stiff brush and damp towel. Apply a fresh coating of grease to the wheel shaft.
Replace the wheels in the reverse order of how they were removed. Reattach the spark plug wire and lower the tiller from its perch on the wooden block.