Oil leak at back of engine

[Timi]

I have just had a o/s driveshaft fitted and noticed an oil leak at the back of the engine, just wondered which gasket this would be and if it is a big job?

Cheers

 

[Budgie]

Pics of where the leak is.

 

[Timi]

Cant get it on a ramp to get a pic mate. The leak is from just above the core plugs