Differential marking information.

[Karguy]

I am beginning to document special markings on 6S281 prior to disassembly. I want to be sure and get everything possible and get it correct. I believe the picture clearly shows D. S. O which I believe indicates Detroit special order, correct me if I'm wrong please. It is the symbols that appear to be C – 3 that I am uncertain about. Is it a C or is it an O or is it something else? Does anyone know what the symbol means? Thank you very much everyone.

[J_Speegle]

The DSO meant a couple of things to Ford. District Sales Order or Domestic Special Order according to Ford documents

Typically we find DSO on the rearend housings like yours for 65 and 66 Shelby applications

The C followed by the number is something found on on early 66 (non-carry over) Shelby's and early Mustangs with 9" rearends. So the two are not IMHO directly related.

Both markings were applied at the Sterling plant that assembled the rearends so the C number markings can be found on cars originally built at any of the three Mustang plants. Orientation and location of the markings can vary but in general when both are present the DSO is to the inside and the C number on the drivers side based on the examples I have pictures of

Yous was likely applied by the same worker as 6S280's rearend since it appears to be the sane handwriting. Possibly both were on the same pallet or container as shipped to San Jose.

Believe that is a "2" between the "C" and the "3"

[Karguy]

Thank you, Jeff, great call on the number two between the C, and the 3. I carefully cleaned a little more of the white and blue overspray and there is a faint two not a dash.
Do you have pictures of Roger's Differential from 280? If not, I can reach out to him for photos. It would be very interesting to compare the two. Thanks!

[J_Speegle]

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