shimming bmax gearbox ??

[fastinfastout]

Hi, recently built up a new bmax as per kit settings, and has only had about 20 runs on it.

I disassembled the rear g/box as it was slipping and thought I needed new diff balls, but to my surprise, the bevel gears has been sheared completely.

I pulled apart the front gearbox, which seemed to have a looser setting, and it looked new.

I dont understand. The rear didnt have any play at all, and its worn really bad.

I read up somewhere here, that to shim it so there is no play, which I built as per kit instructions. Then it should free up on on its own later on.

How do you shim the gear box correctly so that this will not happen again?