Where is the reference sensor on a 1995 Audi A6 Quattro?

[msesmilesalot]

My dad needs to replace the reference sensor but we cannot figure out where it is. Need help ASAP!
Maybe its called the crankshaft sensor?

 

[max]

You got the wrong name, there is no such thing.

Arr, the crankshaft sensor will be at the end of the engine where it connects to the gearbox. its just a small thing with a wire coming out of it. It counts the teeth on the flywheel.
I don't know what A6 you have got and my one is an RS6 and its raining in the UK and 10 o'clock at night.