Pulled an old snowblower from the hedgerow

[Peat]

Soaked auger chains, rebuilding spout cylinder, thinking hydraulic motor on spout directioner is shot, won’t turn at 10-12 gpm.
But question I have is gearbox gear oil level.
There is only one plug with a vent above it, no drain no hi lo oil plugs. Blower was manufactured by a fabricator in Canada.
Sucked old gear lube out, to what level do I refill gear lube?
See photo’s

 

[joeysmith]

The lower plug looks like the fill level to me
One of the cover bolts may be a drain

 

[buickanddeere]

Soaked auger chains, rebuilding spout cylinder, thinking hydraulic motor on spout directioner is shot, won’t turn at 10-12 gpm.
But question I have is gearbox gear oil level.
There is only one plug with a vent above it, no drain no hi lo oil plugs. Blower was manufactured by a fabricator in Canada.
Sucked old gear lube out, to what level do I refill gear lube?
See photo’s

Could be a Hagedorn snowblower. They used to build manure spreaders as well. The factory in Paisley Ontario is gone . No idea if they still exist in any manner anywhere anymore.
I have a 1970's or 1980's Hagedorn single auger blower here . It is in fine condition other than the blower band. One of the Mrs B&D's decorative birch bark logs ledged between the end of an impeller blade and the blower housing. .The band was closer to a half circle vs the intended flat shape. Sledge hammered it back flat where I could reach but...........

 

[47fivewindow]

The old rule of thumb is to fill any gear box half way up the input shaft. Keeps it oiled and lets air pressure leak past the seal.