Cleaning up a WD M20 gearbox shell today and I noticed a drilling that runs from the filler hole diagonally through to the inner edge of the shell intersecting an outer cover screw hole.




I can't see a purpose for this hole, anyone have any thoughts?

email (option): spacemonkeym@gmail.com

I hadn't noticed it before, is it to stop the airlock when you fill up your gearbox with oil?

Rob

email (option): robmiller11@yahoo.co.uk

A good possibility Rob, Hadn't thought of that one.

email (option): spacemonkeym@gmail.com

I wonder if my gearbox has this hole

email (option): ahum@quicknet.nl

Yes they all have the hole (or should) and yes, as Rod surmised, it is to prevent an airlock resulting in a false "full" level.

email (option): n.gentner@bigpond.com