Amismb
Great post!

When I had my RC10 several times I had to shape the teeth on the diff gear and idler. I had several stealth transmissions so set up one that you can assemble the new gear with posi locked outdrives and assembled a so called gear lapping Transmission, put some valve lapping compound in it and spun the outdrives with a drill for a minuet and checked the gear, kept going until I was satisfied with how the idler and diff gear meshed.

Today I have a HD diff case that is setup for lapping teeth on new gears however have not done so yet.

Also I have installed a o-ring on the front and rear outdrives where they contact the diff case or the ring gear and have proved to work exceptionally well.