[Delboy]

Hi just made a shocker of a mistake, I've put engine oil in the gearbox oil when I meant to top up the engine oil... Rode it approx 5miles and saw oil all over the back wheel, obviously from the breather pipe but have I caused a major problem as it sounds a bit noisy. Is it just a case of draining the gearbox oil and putting in the correct oil or have I just knackered something big time

[JimDirt]

Welcome to the site !!

I guess the first question is ... what bike ??? , as you did not mention that ...

You should be ok , if it was just overfilling , as that is kind of what the breather tube shows , is if it is overfilled , that is where it will dump out ..... so yea , drain it , either completely and start over with both sides .... or drain it to the point of being at the correct level , then ride it a bit and check it again , and adjust till it is where it should be , it still might puke a bit out , but after a little bit , it should not continue to overflow ...

My other concern is you mentioned you were adding oil as it was low ..... you should not be using oil unless the bike is brand new or just rebuilt , then it will use a little bit till the rings seat .... , as that might indicate another issue .... I am thinking the "noise" you are hearing is the remaining overfilled oil circulating in the system , it will/should drain back where it should be eventually .... maybe remove the valve cover and make sure the baffles in it are not filled with extra oil ....