The weather's been so good in the last few days that
I'm breaking into the box of PartsShop stuff in the garage,
and dewinterizing the 380SL for a bit of coast driving.
A small benefit of global warming?

One item that I never solved last year was the service
of the differential vent. No problems with access to or
opening the fill and drain ports, but I've never cleaned the
top vent and I understand that's an important parallel job.

I've read the old threads on the subject, and by getting
up close I can -see- what I think is the vent. Short 2 or 3 cm
cylinder on the right upper side of the diff, pointing straight up,
with a metal cap on top of it.

Okay so far. But the cap looks odd. Crimped, actually. It
is close fitting on part of the circumference of its lip, and
flared out on the rest of the lip. It is definitely noncircular,
though I can't tell if it was originally circular and then bent
by the crimping.

It's kinda triangular in shape by feel. And it's visibly a bit
loose to the touch, either by hand or with a tool (no idea
how I'm going to get a box wrench onto this thing). It does
not release by light upward pressure. Haven't been able to
figure out how to turn it counterclockwise with a tool; it will
not turn CCW with finger torque.

Really weird. This doesn't sound like what the vent ought
to look like. Am wondering if this crimp job is someone's
old hack from poor maintenance -- if they lost the real
original vent cap and bodged this new thing on as a quick fix.

If anyone can put me right on this question, I'd be both
amazed and grateful. (Note: My mail's messed up. Replies
that aren't posted here probably won't get to me. Regrets.)

Ron H