i have had gearbox oil ****ing up the speedo drive for a few weeks now and is a real pain

i have been told it could be a blocked gearbox breather, where on the gearbox is it, and what does it look like?

anything else it could be?

thanks

It's a small round plastic thing just under the clutch release arm thingy on top of the gearbox.

Other thing it could be would be the gearbox being overfilled.