Oil Leak at Tranny Switch

[Wolff <quattro200@earthlink.net>]

Patient is a '91 200 tq. Oil occassionally drips onto the right cat. Oil
is comming out of a sender or switch with two wires on it. I don't know
what this part is. Not a backup light switch since the lights still
worked with the two wires disconnected. Not a diff lock indicator switch
since this is a torsen car. Maybe an rpm sender? It's on the right side
of the trans about 6 inches forward of the prop shaft. It is a few
inches forward of the spring loaded exhaust hanger bracket. What the
heck is it and will I lose my tranny oil when I remove it?
TIA,
Wolff