My gear box started to make noise yesterday. It wasn't bad but wasn't good. Opened up the front and rear bulkhead blocks and found 2 small fragments from the bevel drive gear in the front one only (you will find black dust or chunks inside the bulkhead). Replaced it and no more grinding noise. It was literally only missing 1/2 a tooth. Problems when you buy a used car I guess but a simple fix.
Ps- when trying to extract the bevel 14t gear use one of the 3x14mm screws. You can thread the screw about 1/2 a turn into the front of the bevel gear and pull it out... allot easier than pulling everything out.