Now I know why 904 was having issues
I never take them apart...lol
Me neither, cause there's no point in it unless the gear is getting replaced.
But I always used two picks.
One to pry the end of the ring out of gear teeth, and one to start the ring end up over the gear teeth.
Then you can just work it off there.
If no picks then a test light tip and a small flat screwdriver works.
I wouldn't sweat those washers either because they last forever and you can adjust the endplay with the little washer on the front end of the output shaft on top of the front planetary set.
They can be had in different thicknesses, and since that washer doesn't spin on the output shaft because of the odd shape in the center I have even spaced under it with a thin washer with zero problems.
Here in the picture they show three different ones with varied thickness, and you can see the center is shaped so it doesn't spin on the shaft but the end of the input shaft spins in it.
