I would guess you have two hydraulic motors, valving systems etc. You would think a system like this would be reliable and good, I've often wondered why it isnt used more in monos.... (put the engine where you like and drive the prop with a Hydraulic motor
....) However, the reality of hydaulics is they tend to seep some oil
. The maintenance manager that worked for me used to tell me "if it aint leakin', it aint hydraulic". All our big hydraulic machinery powerplants had drip trays under them and they all had some oil
in them most the time.... it still bugs me though. Power steering
on cars doesnt leak much!