I have an '82 Spider with some broken teeth on my diff. ring gear/pinion.
I understand there are 4 different diff. groups.
My mechanic tells me the ring gear in the car is 39/10 with 12 mm bolt holes. He measured the ring as about 13/16" thick.

I prefer new replacement parts rather than a used diff. but am looking for option/advice.
I have located several sets of ring & pinion, but not the exact match.
Can I use a 28mm (1 1/8") gear in its place?
Does anyone have the parts I need? (ring & Pinion).

Thanks for help/advice.

Donald