M46 Output Flange Info?

[Fresh Air Inspector]

Hello All,

I recently converted my 940T to a M46 O/D gearbox. All the bits came from a later generation 740 that used the Rotoflex coupling (Guibo to the BMW and Merkur crowd). Although the install is very working well I would like to have the driveshaft balanced.

To do so I need to have a 'flange adapter' machined that will allow the Rotoflex to be bolted to it. This will in turn allow the driveshaft to be inserted into a lathe chuck for balancing.

The flange is partially completed but I need the dimensions of a critical piece; the 'pin' that protrudes from the gearbox flange and engages a hole machined in the end of the driveshaft, typically protected by a rubber sleeve. Without this 'pin' the driveshaft won't 'self-centre' in the gearbox flange seriously affecting balance as well as overloading the Rotoflex coupling.

Hopefully one of you has a flange kicking around and can measure the diameter and length (millimetres or inches), of this 'pin'?

Looking forward to your input.