I hear the Mugens clicking now. It's common sense folks to shim them up tight. Backlash can cause more failure on older rigs where the bulkhead is worn or older. A tight R & P with grease will mesh in and run great.
Backlash vs tight differ on different tracks and driving styles. Last week, I heard Losi and Mugen both clicking and clacking when braking.
I've given up on trying to help people. It's useless and a waste of time.