Getting ready to change Hyd oil and Case Drain filters, and Hydraulic filter. looking on the LPS site, they list a "Hydrostatic Charge" filter 6686926, as well as the Hydraulic filter. If there is a charge filter, WHERE is it. (I know where the hydraulic filter 6667352 is.) Also opinions: Bobcat Hydraulic oil or cheap 15/40 engine oil?