Move the depth lever up or down until you can feel the encased nut. Just keep the nut in the casing while you crank down the shoulder bolt. You can turn the mower on its side with the oil fill spout down, or empty the gas tank and do the other side. You should also remove the air filter until you're done.

Sure enough, it worked!

I like Toro, they make it easy to work on things like this. I wish other manufacturers were as smart.

I took the time to lubricate both shoulder bolts and axle bolts on both front wheels while I was in there. I even beat the impending thunderstorm.

Thanks!