Bigfish76, few folks get a tractor given to them. That's undoubtedly where Tomcat was coming from.
I don't know the answer to your manufacturer question, but the suggestion on Satoh is where I would start. Use the internet to find Satoh tractors for sale or parts and start asking question there. If they don't know the answer ask them who they would send you to. Keep digging!
Back in the '70's there were several manufacturers of small (eventually called compact) tractors marketed in the US. Yanmar, Satoh, Bolens and Kubota were probably the main ones. There was a peeing contest going on to see who was going to get the biggest market shares. Yamnar united with John Deere. Kubota came together with sales and service and backed up their porduct beyond what the others did. So that's why Kubota has become the leader.
You will have to dig, but that's the fun. Good luck with your new treasure.