When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I think you need the numbers that are stamped on one of the axle tubes. However, the only production info is the day it was assembled. This is from the '87 FSM for Saginaw built rear axles. No reference for BW rear axle ID in the FSM.