Lost the plug that fits into the top (flat fin) hole of the #3 drive.............not sure of it's intended use can somebody tell
me what it's purpose is?............it's either made of plastic or rubber and from the looks of the other drive it's a "squeeze
& insert" type plug.............can you operatyer the drive without this plug?.........here's some pics.

Does it have an Allen screw inside that hole?

Hey Pete. My bravo has that tiny rubber/plastic cap on the tail of the upper unit. It just covers one of the bolts (really cap screw) that joins the upper and lover units together. Cosmetic piece as far as I'm concerned.

Looks like the TRS is the same but I've never worked on a TRS

Mine are long gone. Access plug to undo the bolt for the zinc

Just saw these are 3's. I have bravos so take my comment with a grain of salt

it keeps the bees out

LOL.

I always thought it was a pencil holder for help when taking notes.

Yes. An it's an Allen bolt. Whomever Allen is.

Allen Bolt is the patron saint of galvanic corrosion.... Leave the plastic plug out and shoot some CRC or Fluid Film in the hole once in a while.

So I guess it doesn't matter if it takes in water?..........Like that little plastic/rubber plug would keep water out anyway!.....tomorrow I'll shine a light into it's purpose....thanks all!