Sorry for the extra replies, but having a guess at the actual Toro model being somewhere near the 322-D based on the transmission information I have been reading, but they come in 2WD and 4WD versions as well. Here's a Toro link that may be more helpful if it is the wrong machine.
https://www.toro.com/en/parts?SearchText=Groundsmaster+322-D&SelectedFilterByOption=equipment

This link is also from Toro website for the transmission based on the 327, which appears to be the same as the 345 and 322-D. All of these are from around 1981-1991.
https://www.toro.com/en/parts/partdetails/?id=15710

To get an idea of year, the model serial numbers I found are:-
1984 model 40001-49999
1985 model 50001-59999
1988 model 80001-89999
Sorry, best I can do with limited information.
:-)

Environmentally friendly recycling at it's best