I have included a picture of an unknown differential side gear. Beside the unknown gear is a 1939-1942 Chevy differential side gear - part # 3651053. The overall diameter is 3 5/16".
The unknown differential side gear is 3 1/2 inch in overall diameter. Any ideas what year(s) this gear fits? Is it a 1946 - 1947 - 1948 ish gear ?

If it is for a 1946 and up it will be stamped GM-R.

I have no idea what year it is from but suggest it is from a model without the horseshoe clip to hold the axle in.
Tony

Thanks for the information. The 1939-1942 gears are usually stamped GM 39. The unknown gear is unmarked.

dave