Just noticed last weekend my B1 outdrive is making noise when placed in gear, forward or reverse. It's best described as a low roar. Silent in neutral. No problem with shifting and no vibration. The mechanic at my local marina thinks I should start with a gimbal bearing but that's turning all the time, in gear or not, Right? The transom unit was replaced 6 years ago so that's the gimbal bearing age.

The drive is 28 years old now with probably 800+ hours on it. Could it be as simple as a gimbal bearing? Would it be possible to even hear a noisy drive bearing while in the water?

I would remove top cap and inspect gears?

Drain the oil.
Look for the shine.

Shiny

I definitely will be draining the oil this week.

A bad Gimble Bearing will sound louder when u put the drive in gear,,and it will noisy in the engine bay.

Several people have told me this also so I'm not convinced it's the drive just yet. Too bad there isn't a zerc on the gimbal ring like the original one had.

Mystery solved. Drained the fluid. Only been out a few times so far this season and it's burnt, stinking coal black and super thin after changing at the end of last season. Both drain screws have a significant bush of metal shavings. Propshaft clicking loudly when turned by hand.

She's done.

I would send it to All American Drive Service. Great people and a longer warranty then Merc.

Padraig

George at AADS did mine twice (long story) and I just inspected it after 4 years and still like new with 700hp. Magnets barely have any fuzz on them after 4 years. I also recommend running NEO oil that George sells. Still good and clear after 3 seasons.