rear axle code ID

[OKGMC4]

I've searched all over and can't find any way to decode the numbers. I've seen car axle ID charts, and RPO number ID charts, but not truck axle ID references. I have two axles and would like to know what they are. One is an inline six automatic 69 chevy coil rear and the code is HA1230A. The other is unknown. It came in my 56 GMC when I bought it. It's been in the backyard since I did a C4 rear end swap. It has the panhard hole on top so I know it's a C10 rear and it appears to be a posi. Code on that one is HA0518W. To get the posi I'm thinking I'll cut the coil brackets and weld them onto the leaf rear since I know nothing about setting up rear diff carriers. Thanks for any info...Mike

[LockDoc]

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Try these...

http://67-72chevytrucks.com/vboard/s...d.php?t=578793

The numbers in the Red Chart will be found stamped into the ring gear.

LockDoc

[OKGMC4]

Thanks for the link! I also found this site just now...

http://www.gmcpauls.com/67-72_chevy.htm

It would seem that my posi axle is not supposed to be, as both are HA axles which would indicate 3.73 non posi. I wonder if there is any way to ID the year? Looks like the HA code was used for several years on C10 trucks. I'd have to pull the axles to find out but as I understand some early 12 bolts only had 17 spline axles instead of the regular 30. All the aftermarket 5 lug conversions seem to be for 30 spline.