Foaming Gear Lube Resevoir

[TBOB415]

Hi, I have been chasing a gear lube problem for a while and decided to ask someone who might know. I have a 94' Alpha One hooked to a 3.0L. I noticed the gear lube reservoir losing oil at an increasing rate and could not identify the source. No leaks in the garage, in the bottom of the boat or any sheen on the water. I thought maybe it was the brass fitting going through the transom and decided to check it and replace the bellows while there. Since then the gear lube level remains constant but it foams up while running. I haven't ran it for extended periods after noticing it. Lube in the drain plug is dark, no water down there. This past weekend changed the lower unit water pump looking for oil passage seals that may be bad, did not notice anything that could be leaking. I never noticed cloudy oil in the reservoir before. Any ideas?
Thanks,
Tbob in Louisiana

 

[thumpar]

Is it milky? Have you pressure tested it?

 

[TBOB415]

Haven't pressure tested yet, figured I'd ask to see if there was anything obvious I have missed. Will try that asap.
The lube gets milky but almost like a frothy consistency and then clears up. The level does not increase either like I would expect if water were seeping into the system.
Oil from the lower plug is dark, no signs of water either.
Is that a check valve between the lower unit and gimble? Is it possible its bad?

 

[wellcraft-classic210]

If your loosing oil you have a leak and a pressure test will most likely be required to find it. It may just leak while running for example. If the oil is not milky then water is probably not entering the drive or at least not a lot of it.. Some air bubbles in gear lube are not uncommon right after usage //but it should not be excessive & may vary per brand & quality. If your able to add lost oil then it seems your check valve is not blocked.

 

[crazy charlie]

The gear lube gets aerated while in use so what you are seeing are tiny air bubbles.They subside and the level should be the same while the boat is at rest.Was there any lube inside the drive shaft bellows? there is a seal in the upper unit that will leak while under way but the leaked lube stays in the bellows so it is impossible to find without removing the drive.Charlie