After over 800 hours, the x drive on my main machine has been making more and more "noise". I noticed before that the mesh at the servo was loose and have tried "pushing" the servo closer. This time, after wiping off the grease and having a close look, I could see the little brass pinion was really quite worn. The gear teeth were sharp. (Maybe I should have listened to Al years ago and used place on end instead of place on center!)

Anyway, I also noticed that only 1/2 of the gear is actually used. The pinion is a press fit on the 1/8" shaft, so I heated it up (propane pencil flame) slid it off and flipped it over. The x drive sounds like new again. (This is the kind of thing one has to do if one lives in Canada.)

So, the news flash is: brass servo pinions can be removed with only a little heat. This means one can flip pinions or even swap pinions between servos.