Differential removal on 300SL-24

I have been trying to switch out the differential on my fathers Mercedes for a while now and after disconnecting the driveshaft I have now found out that aside from the normal mounds it has a bold diagonally above it. I cant get there with a wrench or just break it of and then try my luck later. As far as I know the bolt sits in a rubber bearing for shock absorption, so I cant just drill it away or liquidate it. Does anyone know how to get it out? Also sorry for my bad terminal englisch, I am German and dont have the translation for all words. The car is from 1991 with the dog leg shifter.