I assume you need the Eaton 700-015 hydro, wheel horse part number 110959. To my knowledge, they were also used on wheel horse 516-H and 518-H model tractors. Attached is the service manual for your reference. I searched on eBay and found one but it was included in the complete transmission for $250 and only available as local pickup in Quakertown, PA.
https://www.ebay.com/itm/286310716586?_trkparms=itmf%3D1%26aid%3D1110013%26rkt%3D12%26algo%3DHOMESPLICE.SIMRXI%26pid%3D102587%26mech%3D1%26algv%3DStoreBaseV2ForAllSites%26pmt%3D0%26amclksrc%3DITM%26sid%3DAQALAAAAEOgQsKAORvBy51inf54pIIQ%3D%26itm%3D286310716586%26noa%3D1%26brand%3DWheel+Horse%26asc%3D342265%26ao%3D1%26rk%3D1%26mehot%3Dnone%26lsid%3D0%26meid%3D10d8c0c397ce4ace931f84c18db038dd%26pg%3D3418065&_trksid=p3418065.c102587.m173498
Hopefully others on RedSquare has one for sale that is functional, reasonably priced, and close to you. 492-4204 Eaton 7 SM.pdf