Hydraulic and hydrostatic don't cross reference and you have to buy them from the dealer. They are the ones that are ugly priced. (surprise, surprise) The engine oil filter is a NAPA 1324, Wix 51324, $4.60, the primary air filter is napa 6489, wix 46489, $26.88, the inner air filter is napa 6490, wix 46490, $18.33 the fuel filter is Napa 3507, wix 33507, $6.40. (Prices are online recently (2012) from Fleet Filter)