Author Topic: rearend decoding  (Read 4413 times)

Offline 80stepsideguy

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rearend decoding
« on: March 31, 2007, 04:06:00 pm »
Question,
i got 3 12 bolt rearends that are in my shop currently.All 3 have different numbers.But what is different is the rearend have the GM and 2 numbers stamped next to it. 1 has GM79 1 has GM81 the 3rd has GM70 .Are these the years these rearends were built?The GM79 rearend came out of a 77 chevy the GM81 is original for a 1980 truck we own and i dont know where the GM70 one came out of.Can anyone shed some light on this? Also is there anyway to decode these rearends by  a source online?

thanks
pat

Edited by: 80stepsideguy at: 3/31/07 3:06 pm
1980 Chevy c10 restomod:  350/700r4 12 bolt 3.73 rearend iris blue metallic
1998 Chevy 1500 S/B 2wd
1970 cougar convertible: triple white 1 of 1
1931 Ford Model A roadster(family inherited)
2014 Hyundai Tucson Limited(my daily driver)
2023 Kia Sportage X Pro (her daily driver).

Offline joesgarage71

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Re: rearend decoding
« Reply #1 on: April 04, 2007, 08:16:00 pm »
Ther has to be more numbers stamnped in the tubes.

78' K-20 355/SM465/twin stick 205 6" on 36's
14 bolt FF/big bearing Dana 44 4.56 gears

92' GMC C-1500 454/4L80E/14 bolt

Offline shpark2

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Re: rearend decoding
« Reply #2 on: April 19, 2007, 05:32:40 pm »
I found TBK087W02 on the top of my passenger axle tube, 2WD '80 C15 - 12bolt rear.  I think first two are axle code, next is K for GM Canada, 087 is Julian day, W02 is production shift I think.  This is based on this thing I found for Buick, but I'm sure it's similar.  Anyone confirm this, and know what TB represents?  I know I should take rear cover off to make sure, but I got other priorities currently.