If you can change the oil
enough to get it clean (again, I "changed" the oil
9 times), and then keep it clean, you should be able to hold off until your scheduled haul out
. You will need to keep a close eye on your oil condition and level.
This is exactly the position I was in 12 or more years ago. Cleaned up the oil, and installed the oil header tank. Hauled the following winter.
FWIW, Amsoil (I am a disinterested party) sells marine gear
oil that they claim can tolerate 10% water
, or something like that. That's what I use.
Other than the potential water
contamination issue, the gear
oil in a saildrive
has an easy life, I'd say. With the housing immersed in water, the oil is not subjected to extreme heat, as in a truck differential or transmission