Bravo one oil leak

[CruisersRogue]

Hello, I have a Cruisers Rogue 2570 with a 7.4L Merc and a bravo one drive, S/N 0D432903, and transom assy S/N 0D411245. I put my drive unit on about a month ago to get ready for a late season, and noticed the usual small amount of drive oil leakage from the check valve in the bell housing as I put the drive on. It seemed to stop. I then towed the boat from one location to my house, where it lives most of the time. (It still has not been in the water since I installed the drive unit this season). I went out to the boat a few days later and noticed a ton of blue gear oil all over the stern drive, and a puddle on the ground. The oil bottle is pretty much empty.

I just this week got around to pulling the drive unit off to check everything out. As far as I can tell, the o ring around the check valve assy on the bell housing seems intact and undamaged, and was in place when I pulled the drive. The seal cup on the check valve assy on the driveshaft housing seems fine, too. The oil seems to go as far up as just above the check valves on the mating surface between the driveshaft housing and the bell housing, so I assume it's coming from the valves. Where else could it have come from?

Anyway, I'm not too familiar with the setup here, and where the valves lead, etc. How do I figure out if one of the check valves is bad, and which one (driveshaft housing valve, or bell housing valve)? If one or both of them are leaking, wouldn't the o ring that goes around the valve on the bell housing trap any oil and stop it from leaking? Does that mean I just need to replace the o ring? Or should I replace the check valve? Which one? How do I test them? Has anyone ever seen one go bad? Should I replace all the o rings on the mating surface between the driveshaft housing and bell housing while I have the drive off?

Thanks for any help.
-Dave

[NoTies]

Check to make sure the two surfaces were fully mated and touching each other and replace the O ring anyway as it may have a small cut that is only apparent when under compression.