I have a Honda hs624. A few years back while cleaning it I noticed that the gearbox could move if I grabbed it and put pressure on it. I grabbed the fan shaft and was able to move it up and down aprox 1/2". I thought this was odd as my Ariens is solid . I then noticed that the newer Honda's had a brace. Still I gave it not much thought. Then I came across the Honda OPE service manual on cd rom.
While looking through it I noticed some service bulletins and started reading. Honda had a problem with the auger shafts snapping in 2. The Ariens uses a solid shaft going straight through the gearbox and augers to the bucket sides. So it is solid and firm.
Honda used a small nub as a shaft that only goes a few inches into the augers so there is flex. After flexing or hitting some solid ice the auger shafts snapped. Honda would replace the broken shaft, Add a new gearbox housing with boss holes in the top and add a brace. All newer Hondas have this brace. I think flex is bad. The brace should help him in my opinion. When his gearbox moves it puts force on the busings, bearing and seals which could cause his leak.