International 1970 Chevelle LS6 Registry Rear Axle Codes

CodeAxle Ratio
CRU3.31:1
CRVPositraction 3.31:1
CRWPositraction 4.10:1

The rear axle identification code consists of a three letter prefix indicating the gear ratio, four digits indicating the assembly date as month/day, and a single letter suffix indicating the manufacturing location. The identification code should be stamped on the bottom or font of right axle tube either adjacent to the carrier housing or about 8" - 10" inboard from the backing plates. The particular rearend broadcast code is found on build sheets such as RU, RV, or RW. This identification may not always be stamped clearly and the area is often covered with years of road grime so it may take some scrubbing to reveal it.

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Example: CRW 0527B2 decodes to CRW ~ Positraction 4.10:1, 0527 ~ May 27, B ~ Buffalo (G=Chevrolet Gear & Axle, W=Warren, K=McKinnon Industries). If a "1" or "2" exists, it indicates the plant shift number.

Casting Numbers:
12-Bolt Casting #3969278

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The casting numbers/letters on rear end housings may have either a prefix or suffix of "N" or "NF" and no reason has been found yet why they may have one or the other.

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The casting date consists of a single letter, a 1- or 2-digit month number, and either the number 9 (nine) or number 0 (zero) indicating the physical year the rear end housing was cast. This example is May 8, 1970.

A - JanuaryB - FebruaryC - March D - April
E - MayF - JuneG - JulyH - August
I - SeptemberJ - OctoberK - NovemberL - December

 

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Positraction 4.10:1 Ring Gear