>>The easiest way to find out what's leaking is to taste the oil. Everything
>>tastes different.

John,
Why not just stick your finger in the drip and smell the fluid?  Anti-freeze smells sweet, transmission and differential oil has a sort of spicy smell, etc.  It seems to me that this is just as acurate as tasting and doesn't leave a bad taste in your mouth for the rest of the day.
George,
'85 Westfalia