Alpha 1 was pressure tested at 6 psi for 48 hours.

No pressure drop whatsoever.

Boat launched in salt water.

After 1 day in the water boat pulled out - the gear oil was clear.

After 1 month in the water the gear oil was milky.

The milky oil was drained. Pressure tested again - 6 psi for 48 hours - holds pressure OK.

Could anyone guess what may be wrong?

Thank you.

Pressure test means nothing. You need to do a vacuum test. We see it all the time, a drive will hold pressure but not the vacuum test. (pressure aginst the seal will cause it to seal itself)

If there are no visible leaks, it probably is a shift shaft seal.

Kurt.

I had a 2002 Bravo out of the box that oil would disappear from . Sit in the driveway all week and it was fine. After checking everything possible I was able to take a quarter turn on all the bolts between the upper and lower gearcase. Never did SEE a leak but this stopped it .

Like Biggus said; you have to do both the pressure AND vacuum test. And I would like to see them hold 10-12 #, not just 6. That being said; if there is no fish-line around the prop-shaft, it's the shift shaft seal 90% of the time. --- JP