Oil for a Craftsman Snow Blower with 187776 Hydrostatic Transmission

I am working on a Craftsman 944.527700 with a hydro transmission that was leaking oil and would not turn the wheels (belt was installed incorrectly). It appears to have been overfilled or perhaps needs purging.  Does anyone know who makes these transmissions, how much and what type of oil they require?

Thanks  AVB.  I found the answers about the same time as your helpful post. 
 
The 187776 transmission is made by Hydro-Gear and the cross reference is 311-0410 on their site. There is a downloadable manual on the website.  It takes 1.75 liters of 5W-30 synthetic motor oil and there is a purge procedure to get air out of the system.