I have finally got around to replacing the slipping clutch on my 1150. Initially I thought that this was due to oil contamination and there is signs of oil in both the engine and g/box bellhousings. The clutch plate and components do not appear to be oily and the plate is not showing signs of contamination and is worn down to 5mm. Question being is it normal for oil to be present in there (I have seen posts saying oil leak between G/box and engine was acceptable) or do I rip off the flywheel and start replacing oil seals (I would rather not)