It’s actually hard to see this while it’s happening but this is what’s going on when you hear those nasty klunks on those two larger gears.
aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia aia