The casting is close but different. It look like the one that came out of my 81 380SL. I pulled it yesterday hoping to get an answer from it. The 722.303 VB at 13a. Your picture seems to suggest that there needs to be either check ball 13 or check valve 13a at that location. So, one hole down only 17 more to go.

LOL

P.S.

I now believe it is check ball 28. It's printed in black and white (Bei den Getrieben 722.315 und 722.303 wird die Ventilkugel (28) nicht eingebaut). Loosely translates to "With Transmission 722.315 and 722.303, the valve ball (28) is not installed." Thank you Google Translate.

I hope this does it.

Thanks for the solid