Remove the cover off the worm gear box by removing the bolts that hold the cover in place with a wrench set. The worm gear box is located between the tiller blades.
Scrape the grease out of the gearbox with your finger. If necessary, use a rag to help scrape out the grease. Rotate the gear manually to help move the grease in the lower half of the gearbox to the top.
Fill the gearbox with replacement lithium #0 grease until the grease rests just below the top of the gearbox.