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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: CA76K10 on November 02, 2018, 09:22:15 pm

Title: Help with codes on a 12 bolt rear end
Post by: CA76K10 on November 02, 2018, 09:22:15 pm

Having trouble figuring out my rear axle. 12 bolt with the following markings...TBH(or TRH?) W217 2 on pass axle tube,  CN2 and H 2 2 on back driver side casting and finally GM58 and 3896839 N on the front of the casting. Any help is appreciated!

Title: Re: Help with codes on a 12 bolt rear end
Post by: CA76K10 on November 02, 2018, 09:24:52 pm

Having trouble with photos

Title: Re: Help with codes on a 12 bolt rear end
Post by: Irish_Alley on November 06, 2018, 09:14:19 pm

try this http://forum.73-87chevytrucks.com/smforum/index.php?topic=6428.0

Title: Help with codes on a 12 bolt rear end
Post by: blazer74 on November 07, 2018, 01:44:04 pm

KBH 3:73  open
W217 2      Warren Michigan Plant, 217 day of the year,  shift 2

Should be a date code on the center section web next to the vent tube starting with a letter for the month then 1 or 2 numbers for the day and the last number for the year. Should be a 6 for 76.

My 74 12B date code is A84. (January 8 1974)

CN2 or H 2 2 ?  Where is the H 2 2.
The GM59 and long 3896839 N number are just casting numbers for 12 bolt as far as I know.


(https://uploads.tapatalk-cdn.com/20181107/19fbb517b99c0ca0a67f3510c32ee6a1.jpg)(https://uploads.tapatalk-cdn.com/20181107/c0c6a62307a7ff79ad1b8af4e3e472d8.jpg)
(https://uploads.tapatalk-cdn.com/20181107/844a80a55d03fcdec02706ab6775a4fc.jpg)