I have an oil leak where the motor meets the transmission. My mechanic thought that at this point it is not worth the $ to tear things apart at this point, but there is a burnt oil smell that occurs frequently coming from under the car. Any opinions on this?

Get a strong trouble light, the oil leak may be at the back of valve cover or the cam adjuster seals. If these leak, it's know the oil will hit the exhaust manifold causing an oil smell, especially when you come to a stop. What year/ engine?

it's a 99 2.8 quattro wagon

Replace your rear main seal. This means dropping the tranny to do the work.

Thanks for the tip. Any idea what the nut on that is? The car has almost 130K and I'm at that point of questioning repair vs replacement.