Pro EX 4/0-2 slop in main gear and drive shaft assembly

[bondstreet]

I am working on a friend's Pro EX 4/0-2 that has some slop in main gear and drive shaft assembly that causes the spool to ring when the handle starts turning. I don't think it will hurt anything, but I would like to fix it. Looking at the main gear and drive shaft assembly and the schematics, it looks like it can be a little difficult getting it apart and back together. Are there any tricks I should know about before I mess with it?

[Keta]

The shift mechanism is a little tricky but the rest is easy.

[alantani]

i'd have to take a look to get a better idea, but it sounds like maybe just a little slop in the gears (gear lash).