Hey, I have a 2005 Mitsubishi 380 in 5 Speed MANUAL.....there is a build up on oil on top of the gearbox running down to the bottom, we could not find the leak, We though mabey when we bleed the clutch last time we forgot to clean up, so we degrease and wash the engine bay spotless..nice and shiny...Anyways today after work i thought i would check up on it....And there it is OIL......Its to bloody hard to tell if its engine oil, gearbox oil, it gets cooked with the heat generated, We choecked all the oils and fluids, all of them are perfect condition and correct levels... minus the boiled brake fluid....It sometimes is hard to get into gear at times......And sounds like there is vaccume from the engine bay when you release the clutch....I know its not brake/clutch fluid leaking becuase the brake fluid is GREEN in colour, the oil thats leaking is yellow.....Its a damn mystery leak

Can someone help me as to where it could be coming from....

If it's yellow it's not engine oil unless you just change your engine oil. Engine oil are usually black after few k of driving.

I would suspect it should be gear oil. You need to clean it up again and see where exactly is the leak.

I would imagine you would be able to smell the difference between engine and gearbox oil?

The gearbox breather is a black rubber item next to the shift levers, this may be the source of your leak, but it's very unusual to have any thing come out.