So my gimble bearing died. I took it to the shop and had that repaired. When i got it back, I took it out and realized quickly that the power steering was dead, and I had to struggle to get it back on the trailer, pulling hard on the wheel that wouldn't turn. Later found out it was entirely empty of power steering fluid and we refilled it- problem solved, with the engine running now its super nice turning the wheel.

However during this trailered test, it is suddenly a new noise that wasn't there before i got it repaired. When you turn the wheel all the way to the lock, it starts making a banging noise.

I have a youtube demonstrating this noise but it won't let me paste it because i'm new here. if you go to youtube / watch?v= and put 9b5iNkW4zFo?t=15 you'll get it. You can see that the noise starts at the point where i'm turned far enough that the power steering actuator or whatever it's called actually moves out towards the camera. I don't know if that is normal or not. Seems not. You can also hear a hissing sound when it goes out to one side.

So... this noise happens when the prop is NOT engaged, so the u-joint is not the problem. It is "banging" at the frequency of the engine's girations, but the sound isn't transferring into the engine. It is transferring into the hull (checked w/ stethascope) and the entire lower unit. When the we stethascoped the power steering pump/belt drive area, there was NO sound there. The sound comes 100% back to where the arm goes from the power steering to the lower unit.

My other thought is we simply dumped power steering fluid into a bone dry power steering tank, so maybe this is similar to an air hammer in a water pipe?? do i have air bubbles? what else causes this sound?

The other odd thing is that the vibration isn't visible at all in the power steering unit itself... with this sound, you'd think i'd see it vibrating. Nothing.

when i had it out with this noise, it banged just as fast as the RPM of the engine of whatever speed i was going. But again, happens when prop is not engaged... were i to simply not turn so far towards the lock, the boat wouldn't be as mobile as is generally necessary. it's the last half a foot of travel on either side for the lower unit.

it is also worth noting that there is a little drip you can see coming out of the power steering at the end of the actuator (if i am using the word right) and a small puddle underneath of power steering oil...

Thanks for any advice on what to look at here!!!

When ever the motor is running the drive shaft is also turning, makes no difference if its in gear or not. I would say the folks that put your gimbal bearing in did not do it right.

To post a vid, save it on a place like you tube and link it here

Yeah, U-joint bad or engine alignment problems. Low probability is potentially the flywheel coupler also (but it would usually make noise in other positions as well as "hard left or hard right").
OR they hammered too hard in the wrong places on the new bearing and damaged it. It's DEFINITELY related to the repair, so don't let them try to convince you otherwise.

Part of a gimbal bearing job is:

Once the bearing is removed, blow out the grease port, pump all the old grease out until new fresh grease is all the way thru the tube. Make sure the owner knows it is there to grease the bearing. Put a fresh rubber cap on it if it is missing.
Inspect the U-joint, check for wear, play, or stiffness (I would replace it if I knew it was over a few years old).
Inspect the gimbal pivots, make sure those are fixed before it goes back together.
Check engine alignment before it goes back together.
Inspect all bellows - might as well replace all of those unless they are very very fresh.

Youtube info you posted does not come up with anything