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rear end id tag?

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12K views 11 replies 8 participants last post by  JG283  
#1 ·
Just curious about the stamp on the sheet metal tag on my 3rd member. It was a little rusted so I cleaned it up some and thought I saw an 8 while using a magnifying glass. Could have been me just wanting to see something. Went back out and did a light wire wheeling and now I see nothing at all. I know, dumb ____ (you fill in the blank). :eek: Can anyone tell me what I should be seeing on this tag? The date code on the 3rd member is: A317. From what I can tell this is Jan 31, 1957. The casting number is 3725899 and I have nothing to refer to for this. There is also GM 18. The ring gear has 37 teeth, the pinion has 11 so I calculate it out to 3.36. Is there anything other info on the "tag" that I need to know?

I also bought a replacement 3rd member that I was told was from a 58 sedan. The date code is J312, does this mean Sept. 31, 1962? The casting # is 3790614 and GM 6, 37 ring, 12 pinion = 3.08. I appreciate any help.

Thanks
Rog
 
#3 ·
Yes, this tag is round and the only hole in it is the one that the stud goes through. I thought I had seen a thread on TriFive that mentioned them also. But I did a search today and must have looked at 300 or more different posts with no luck. I finally gave in to frustration and posted another.

Rog
 
#5 ·
MikeKy55,

Thanks for the info. I copied the picture for future reference. The interesting thing about my tag is that it is the wrong one. I have the 3rd member disassembled and the number of teeth on each is as I listed earlier. Guess someone used what they had at the time. Probably replaced it and used the tag from the original.
Thanks again

Rog
 
#12 ·
lonewolf85 said:
According to the comment,s posted in the thread about a week ago the book show 336 and 355are incorrect a336 has one hole and a355 has two? :confused: Randall
Click to expand...
I noticed that too.....because I was like the OP, couldn't find anything stamped on the tag. Mine came off of an untouched 85K 57 with 3:36, it was round with the bolt hole only. I've learned something though!
 
R
#10 · (Edited)
You can also cross check to the stamped code that is located at 9 o'clock on the 3rd member housing. Two letters and 3 numbers. The first letter indicates where it was assembled, the second letter is the gear ratio. The numbers are the date code. I have a code list from the CCI Tech Book, and it's probably on the site somewhere.

The 899 casting number is just the one used on all non-posi's for several model years. The "GM18" or whatever is a casting tooling identifier and doesn't mean anything to us.
 
#11 · (Edited)
Rog.....You should be able to see some letters stamped on the rear as well....In this case the first letter, A indicates manufactured in Detroit...The letter B would indicate Buffalo....The second letter, B on a 55/56 rear indicates a 3.55 ratio and on a 57 its 3.36....See Danchuk's Original Specs: http://www.trifive.com/specs/19. Original Specs.pdf

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