Originally Posted by JJW
Correction, i found the drain plug, a small square plug at the bottom of the cover. It is hidden by the panhard rod. That will have to come off. Now off to find that good mechanic ;-)

Well done. It is hard to see if you don't know where to look.Seems at a glance to be merely another backplate bolt.

I have never heard (save once) of a BTR failure unless the wrong fluid has been used. BTR is very precise on that.
What was in there and what does the Italian mechanic want to use?

It does not take a good mechanic to drain a BTR. Merely someone knowledgeable enough to use the right fluid.

L.