Hi, I'm replacing the starter on my 82 240d manual trans. Doing it from above. All is well except the rear two bolts on the starter: on the back end they're big circles, and on the front end they're round as well. I've read they require a 10mm wrench socket, though my suspicion is you need a 10mm allen KEY to fit in the rear circle and turn those two bolts. Can anyone confirm?

...I'll answer my own question. I used a 10mm hex socket with a 10mm ratcheting box end on it, or a 10mm "male" version of the 10mm socket used to get the two front bolts on the starter. So it is like an allen key, only it's an attachment to a socket wrench.

Got the old starter out and new one in from the top by unfastening the coolant line from the wheel well, just so it could move a bit closer to the engine and let the starter through on the wheel side.