If I understand you correctly, 931 for example, denotes features of the rear-axl, but not the plant where it was manufactured. That gives me 2 more questions. 1) how do I decode those three digits? and 2) where is the plant identified, if at all, on the rear-axl?
Thanks,
-Richard
You are understanding.
1) I don't know if there is a decode of those digits. All the "931" axles would be identical. Perhaps a number Ford Gearing assigned?
2) I'm not sure on the axle. Manufactures put codes on which track where and when components were cast/assembled. That is part of tracking failures. The axle housing might have a stamp somewhere for where it was drawn? I'm just guessing. The carrier (holds the gears) has a Foundry cast in it IIRC. Just like the engine blocks have casting letters and numbers that have been decoded to which foundry, Date, Shift, vehicle line it was designed for.
The rear axle assembly is several sub components, possibly made at different locations. The axle housing, the carrier, the gears the axle's themselves.
On our Build Sheets, those told the final assembly plant what to put on a given chassis. As you have seen, some are numbers or letters, or combinations. A recent topic on another Ford forum was about fan belts and related to what is seen on Build Sheets. The Build sheet has stuff like "C6OE" for a belt in a certain pulley location. Other parts have color codes on the build sheets. The front and rear springs comes to my mind as they have stuff like "2YL2BN" (2 Yellow paint marks, 2 Brown). All so the assembly line workers can quickly walk to the correct part bin and grab the correct part.