This looks like a typical axle seal leak to me. Out of all the fluids that come out of our vehicles, I would say axle oil smells the worst, followed by ATF. ATF is easy to spot, because it should have a reddish brown tinge (unless it is badly burnt) and it would be coming from under the middle of your VX.

Axle leaks are pretty easy to spot too, because you will have staining and a drip that accumulates around the area where your axle goes into your differential. To fix these leaks, you will need to drop the front axle and replace the seals on the inside. I did mine last Sept.

Bart