We have the same gear box with 3400 hours on the clock and about 25k nm in "freewheeling" mode while sailing (previous owners) and it is in perfect condition. Change the fluid yearly, almost exactly one quart of ATF, so its really easy, and she'll run for a long time. Changing the ATF takes me less than 5 minutes and costs $3.50.... I still prefer the factory Yanmar, Westerbeke or Universal mounts (current versions only). I found the PYI's on a Yanamr transmitted more vibration to the hull... Still a decent mount and better than most...