would the transmission oil be changed on zues drives,or just leave it alone on 5 year old boat with 1000 hours and no service records showing it had ever been done?
I would change it annually regardless of (low) hours. I’d also be worried about what other maintenance was deferred on a 5 year old boat that hasn’t even had the transmission fluid changed.
It's the same stuff Merc put it in all their top drives. In fact, Hi Perf goes in just about every bottom end I do (I buy it in very large drums). Best buy ever.