1968 OMC Stringer

It broke AGAIN!
New member here. Very frustrated with an old stringer outdrive in this V/8 Chevy powered Allmand. A type 3 I believe.
I have replaced the drive 3 times in as many years with used ones that have been taken off running boats. They work for a few hours then something always breaks. I do use proper lube and check it often.

Over this past weekend I was on a 12 mile run in from diving, not pushing hard at all when the drive suddenly made a loud bang that sounded like it popped out of gear.
I idled down and went to neutral but found the drive still grinding away no matter what position the gear lever was in, so I shut it down right away.
This is an electric shift.
6 miles out in a hard blow, perfect timing...
Any ideas what could have happened? I have not taken the drive off yet, just going to winterize and deal with it in the spring but would like to know if anyone can help clue me in to what I am in store for. I did pull the top dipstick and found the lube mostly GONE! WTF? Where did it go in 5 hours running time.
I am assuming the lack of lube caused the failure, but what broke?
Thank you.

 

are you using the v8 drive?
They were reliable as long as you had the correct oil in them and both housings actually had the oil in them
Pressure test the next drive.
Take the lower unit off and then the water pump and you might see the oil leak

 

I have a lot of experience with these, is it the upper drive or lower drive that is failing?

 

The upper gear case either had the v8 gears or the 6 cylinder gears.
I recall a label on the upper housing indicating horse power max. It was on the top oil chamber cover plate.

The lower gear case did not matter