arapoda:

Pic #3:

Pull off the big Gear then pull off the e-clip. Disassemble the output shaft and pull the bearing off. Add the washer from pic one to the outside of the diff gear (add 3 -4) then reassemble. The washers go inbetween the bearing and the big gear. If you go to HPIRacing.com that have the 18ss manual online. That is the picture I was trying to include.

Make sense?

What confuses me is that you have the pot metal input gear on the table and also the hardened steel one in your hand? Which one are you installing? The above is for the 18ss hardened steel ones. I hope that is what you are installing.