Here is a crummy diagram (my coordination with the mouse still isn’t good). The critical surface is the
45.00 mm dia surface that the seal slides over. This (and the lead-in taper) needs to be finished as the
transmission axle flange where the seal runs. You don’t want the tool damaging the new seal.
The 2.0 mm dimension determines the axial position of the installed seal.
None of the other dimensions are critical.
In my diagram I show two lathe centers. This should be easy to make on a metal lathe;
three diameters and three faces plus one finished surface with taper.
The hollow center is necessary for clearing the threaded piece in the '65-'67 non-simplified differential.
Revision 2
I bought this tool from Porsche in 1968.
It could use some TLC to get rid of the old sealant.
Best,
Grady