Thanks - so I ended up jumping on this today. Bottom line is I wish I had easy access to SHC100 or even 28, but I don't. Really not a fan of putting a petroleum grease on these gears so I looked for options. I found some red Amsoil synthetic NLGI 2 grease. I read the applications before I put it on and we'll see how it does. It's compatible with lithium grease, so while I did clean the grease that wasn't on the gears, I wasn't too worried about it. Can always swap it for something else. Very glad I did open up the motor though. The job was easy and the gear teeth seemed to be lacking grease. See the photos below. Lots of white lithium grease in areas that won't help a whole lot. Cleaned it up and put the new grease on like this Rize video, below, shows. Took it for a quick spin and so far so good. Motor is nice and quiet.
In case someone is looking at this thread and wants to know how to get the motor apart and do this, I did it nearly the same as in the Rize video (although I didnt fully remove the planetary gear assembly from the motor).
1) Take the wheel off.
2) Unscew the retaining bolt by the brake rotor
3) Flip the motor/wheel over. There's a spacer that will likely fall out from the rotor side. This just goes on the axle immediately behind the retaining bolt. Remove the screws on this side of the motor. I think there were 6 of them.
4) Make sure the electric line is coming out the slot on the side of the axle so it is protected, then put some pressure on that side of the axle. I just put that side of the wheel the the garage floor and gently pushed down. This pushed the motor out the side.
5) Inspect gears for any broken teeth (I didnt see any).
6) Wipe up grease that's not on the teeth, both on the planetary gear assembly and the interior of the housing near the gears.
7) Apply some grease to the gears inside the the housing (see the Rize video).
8) Gently put the motor back into the housing. If it doesn't want to go in the final 1/4 inch, then rotate the axle slowly just a bit while gently pushing it in. This will align the planetary gear teeth with the teeth in the housing.
9) Put the spacer and retaining bolt back on the rotor side and screw the screws back in on the other side.