I bought a Hustler fastrak from a friend which needs a left hand hydro. The set up is from about 2006 it has an 18 hp engine and 52" deck. the shop he took it to to have it worked on just about destroyed the hydro housing. the part number is 788067 / 311-2600L. any ideas on where to find a cheaper one ( college student) or is it possible to use a newer hydrostat drive to replace it without replacing both sides? Thanks for any help!