Re: Volvo 250 w/270 outdrive
If you have milky oil in the bellows, that's because water gets into the bellows then into the drive because the seal is not designed to keep water out of the drive only oil in. When the drive cools down after running, it will actually suck water into the drive if it's in the bellows.
Those bellows are thin, and should be replaced after 2 seasons. Getting water in the bellows also allows water into the engine bellhousing intermediate bearings which requires an engine pull to replace.
You also don't have to remove the complete drive to change the bellows. Removing only the upper gear box is all that's needed. Changing the gear lube, ujoint bellows, lubing the ujoints takes about an hour of easy work once you are familiar with the process.
Just remember to use all new orings when putting the upper gear box back on, and keep things CLEAN.
There are also shims between the upper and lower that must be in place when you put it back on.