found it.
so, the 'donor' diff says 3.46 and the 'current' diff that's on my '85 wagon says 3.07.
i don't believe i have the shims for the donor...as he just gave the the differential itself, nothing mounted to the car.
does it sound like a bad idea swap anyway, for a 70% highway driver?

also, how do you know when an axle shaft's bad?

__________________
-lee
'83 300CDT (286k)

former proud owner of:
'85 mercedes euro 300TD
'80 mercedes 300TD
'77 mercedes 280e
'80 mercedes euro 250
'82 mercedes euro 250