Stamped numbers on Eaton posi cases C2, C3 (early ?)

[Wayne M.]

Noticed a stamping on several '65-up posi cases I have. Wondering if others have seen these and if there's an interpretation and possibly a correlation with the cast date (Julian ?) on the case, and even the assembly of the case in the diff. carrier ?

Here's the pics from two differentials, to get the ball rolling. First two are from my (I believe original) 3.70 ratio [carrier stamped FA_7_15_65]. Second pic is a close-up of the case stamping 'F29F6' on the first, where I've increased the contrast for legibility. This posi case is cast EDB 30117 (first design Eaton, for 3-series ratios 3.08 thru 3.70) and has a cast date (?) of *353*.

The third pic is of another 3-series 1st design '117' (don't know the car it came from, but the R&P 3.08 gears are dated June'66/Feb'67). The stamped code is 'C31H' and the Julian cast date (?) is *53*.

I have more examples, but I'm leaning to an interpretation that the stamping is an assembly date of the posi case (not the differential carrier, but it could be close).

Any thoughts ?

[Ronald L.]

Re: Stamped numbers on Eaton posi cases C2, C3 (early ?)

Casting dates Julian. I recall in one of the GM gear plants, many years ago, more than one person whose job it was to inspect and stamp, gear sets, cases, etc.