1958-1970 Chevy Rear Differential code Identification



Using the charts below, you will be able to learn alot about the rear differential in your classic full size Chevy. The gear ratio codes are located on the front passenger side of the differential as shown in the illustration below. This code will tell you the ratio, whether it is posi or not, any special notes and what plant it was made at.





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   1958    1959    1960    1961    1962-64    1965-69    1970



1958

Code Ratio Posi? Special notes Build plant
AA 3.55 No 3 speed Detroit gear & axle
AB 3.36 No Powerglide Detroit gear & axle
AC 4.11 No 3 speed, O.D. Detroit gear & axle
AK 3.55 Yes 3 speed Detroit gear & axle
AL 4.11 Yes 3 speed, O.D. Detroit gear & axle
AM 3.36 Yes Powerglide Detroit gear & axle
BA 3.55 No 3 speed Buffalo
BB 3.36 No Powerglide Buffalo
BC 4.11 No 3 speed, O.D. Buffalo


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1959

Code Ratio Posi? Special notes Build plant
AA 3.55 No 3 speed Detroit gear & axle
AB 3.36 No Powerglide Detroit gear & axle
AC 4.11 No 3 speed, O.D. Detroit gear & axle
AK 3.55 Yes 3 speed Detroit gear & axle
AL 4.11 Yes 3 speed, O.D. Detroit gear & axle
AM 3.36 Yes Powerglide Detroit gear & axle
AW 3.08 No 348, Powerglide Detroit gear & axle
AX 3.08 Yes 348 Detroit gear & axle
BA 3.55 No 3 speed Buffalo
BB 3.36 No Powerglide Buffalo
BC 4.11 No 3 speed, O.D. Buffalo
BE 3.70 No 3 speed, O.D. Buffalo
BH 3.70 Yes 3 speed, O.D. Buffalo
BK 3.55 Yes 3 speed Buffalo
BL 4.11 Yes 3 speed, O.D. Buffalo
BM 3.36 Yes Powerglide Buffalo
BW 3.08 No 348, Powerglide Buffalo
BX 3.08 Yes 348 Buffalo
FE 3.70 No 3 speed, O.D. Detroit gear & axle
FH 3.70 Yes 3 speed, O.D. Detroit gear & axle


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1960

Code Ratio Posi? Special notes Build plant
AA 3.55 No 348 w/P.G. or 6 cyl. w/3 speed Detroit gear & axle
AB 3.36 No V8 w/3spd or 6 cyl. w/P.G. Detroit gear & axle
AD 3.36 No 283 w/3spd-Taxi or 6 cyl. w/P.G. taxi Detroit gear & axle
AG 3.55 No 6 cyl. w/3 spd. taxi Detroit gear & axle
AK 3.55 Yes 3 speed Detroit gear & axle
AM 3.36 Yes   Detroit gear & axle
AW 3.08 No 348 w/T.G. or 238 w/ P.G. Detroit gear & axle
AX 3.08 Yes 348 Detroit gear & axle
BA 3.55 No 348 w/P.G. or 6 cyl. w/3 spd. Buffalo
BB 3.36 No V8 w/3spd. or 6cyl. w/P.G. Buffalo
BD 3.36 No 283 w/3 spd-taxi or 6cyl w/P.G. taxi Buffalo
BE 3.70 No 348 w/4 spd. Buffalo
BG 3.55 No 6 cyl. w/3 spd. taxi Buffalo
BH 3.70 Yes   Buffalo
BK 3.55 Yes 3 speed Buffalo
BM 3.36 Yes   Buffalo
BW 3.08 No 348 w/T.G. or 283 w/P.G. Buffalo
BX 3.08 Yes 348 Buffalo
BZ 3.08 No V8 w/P.G. taxi Buffalo
FE 3.70 No 348 w/4 spd. Detroit gear & axle
FH 3.70 Yes   Detroit gear & axle


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1961

Code Ratio Posi? Special notes Build plant
AA 3.55 No 348 w/P.G. or 6 cyl. w/3 speed Detroit gear & axle
AB 3.36 No 283, 348 or 6 cyl. w/P.G. Detroit gear & axle
AD 3.36 No 283 w/3spd-Taxi or 6 cyl. w/P.G. taxi Detroit gear & axle
AK 3.55 Yes   Detroit gear & axle
AM 3.36 Yes   Detroit gear & axle
AW 3.08 No 348 w/T.G. or 238 w/ P.G. Detroit gear & axle
AX 3.08 Yes   Detroit gear & axle
BA 3.55 No 348 w/P.G. or 6 cyl. w/3 spd. Buffalo
BB 3.36 No 283, 348 or 6cyl. w/P.G. Buffalo
BD 3.36 No 283 w/3 spd-taxi or 6cyl w/P.G. taxi Buffalo
BE 3.70 No 348 w/4 spd. Buffalo
BH 3.70 Yes   Buffalo
BK 3.55 Yes   Buffalo
BM 3.36 Yes   Buffalo
BW 3.08 No 348 w/T.G., 4 speed or 283 w/P.G. Buffalo
BX 3.08 Yes   Buffalo
BZ 3.08 No V8 w/P.G. taxi Buffalo
FE 3.70 No 348 w/4 spd. Detroit gear & axle
FH 3.70 Yes   Detroit gear & axle


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1962-1964

Code Ratio Posi? Special notes Build plant
AA 3.55 No 6 cyl. w/3 speed Detroit gear & axle
AB 3.36 No 3 speed Detroit gear & axle
AC 3.70 No 3 speed O.D. Detroit gear & axle
AD 3.36 No 3speed, P.G., Taxi Detroit gear & axle
AE 3.55 No Metallic brakes Detroit gear & axle
AF 3.70 No Metallic brakes Detroit gear & axle
AG 3.36 No Metallic brakes Detroit gear & axle
AK 3.55 Yes   Detroit gear & axle
AL 4.11 Yes   Detroit gear & axle
AM 3.36 Yes   Detroit gear & axle
AN 3.55 Yes Metallic brakes Detroit gear & axle
AP 3.70 Yes Metallic brakes Detroit gear & axle
AQ 3.36 Yes Metallic brakes Detroit gear & axle
AR 3.08 Yes Metallic brakes Detroit gear & axle
AS 4.56 Yes   Detroit gear & axle
AT 4.11 Yes Metallic brakes Detroit gear & axle
AU 4.56 Yes Metallic brakes Detroit gear & axle
AV 3.08 Yes Police Detroit gear & axle
AW 3.08 No 327 w/ P.G. Detroit gear & axle
AX 3.08 Yes   Detroit gear & axle
AY 3.36 No Police Detroit gear & axle
AZ 3.55 No Police Detroit gear & axle
BA 3.55 No 6 cyl. w/3 spd. Buffalo
BB 3.36 No 3 speed Buffalo
BC 3.70 No 3 speed O.D. Buffalo
BD 3.36 No 3 speed, P.G., Taxi Buffalo
BH 3.70 Yes   Buffalo
BK 3.55 Yes   Buffalo
BM 3.36 Yes   Buffalo
BW 3.08 No 327 w/P.G. Buffalo
BX 3.08 Yes   Buffalo
JA 4.11 Yes Z-11 Detroit gear & axle


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1965-1969

Code Ratio Posi? Special notes Build plant
DA 3.08 No 10 bolt Dana
DB 3.36 No 10 bolt Dana
DC 3.55 No 12 bolt Dana
DD 3.31 No 12 bolt Dana
DE 3.31 No 12 bolt, police Dana
DF 3.07 Yes 12 bolt Dana
DG 3.08 Yes 10 bolt Dana
DH 3.31 Yes 12 bolt Dana
DI 3.36 Yes 10 bolt Dana
DJ 3.55 Yes 10 bolt Dana
DK 3.55 No 12 bolt Dana
DL 3.70 Yes 10 bolt Dana
DM 3.73 Yes 12 bolt Dana
DN 4.10 Yes 12 bolt Dana
DO 4.56 Yes 12 bolt Dana
DP 4.88 Yes 12 bolt Dana
DQ 3.55 No 10 bolt Dana
DR 3.07 No (this code only used for 1965-67) 12 bolt, Metallic brakes Dana
DS 3.07 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Dana
DT 3.08 No (this code only used for 1965-66) 10 bolt, Metallic brakes Dana
DU 3.08 Yes (this code only used for 1965-66) 10 bolt, Metallic brakes Dana
DV 3.31 No (this code only used for 1965-67) 12 bolt, Metallic brakes Dana
DW 3.31 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Dana
DX 3.36 No (this code only used for 1965-66) 10 bolt, Metallic brakes Dana
DX 2.73 No (this code only used for 1968-69) 12 bolt, Metallic brakes Dana
DY 3.36 Yes (this code only used for 1968-69) 10 bolt, Metallic brakes Dana
DZ 3.55 No (this code only used for 1965-67) 10 bolt, Metallic brakes Dana
EA 3.55 Yes (this code only used for 1965-68) 10 bolt, Metallic brakes Eaton
EA 2.56 No (this code only used for 1968) 12 bolt Eaton
EB 3.55 No (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EB 2.29 No (this code only used for 1969) 12 bolt Eaton
EC 3.55 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EC 2.29 No (this code only used for 1969) Eaton
ED 3.70 No (this code only used for 1965-67) 10 bolt, Metallic brakes Eaton
ED 2.56 Yes (this code only used for 1968) 12 bolt Eaton
EE 3.70 Yes (this code only used for 1965-67) 10 bolt, Metallic brakes Eaton
EF 3.73 No (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EF 2.56 No (this code only used for 1969) Eaton
EG 3.73 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EG 2.56 Yes (this code only used for 1969) Eaton
EH 4.10 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EI 4.56 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EJ 4.88 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EK 3.70 No (this code only used for 1965-68) 10 bolt, Overdrive Eaton
EL 3.73 No (this code only used for 1965-69) 12 bolt, Overdrive Eaton
EM 3.07 No (this code only used for 1965-69) 12 bolt Eaton
EN 3.07 No (this code only used for 1965-69) 12 bolt, Police Eaton
EO 3.55 No (this code only used for 1965-69) 12 bolt, Police Eaton
EP 2.73 No (this code only used for 1965-68) 12 bolt Eaton
EQ 3.07 Yes (this code only used for 1965-68) 12 bolt Eaton
ER 2.73 No (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
ES 2.73 Yes (this code only used for 1965-67) 12 bolt, Metallic brakes Eaton
EU 3.36 No (this code only used for 1967-69) 10 bolt, Eaton
EX 3.70 No (this code only used for 1967-68) 10 bolt, Overdrive Eaton
EY 3.70 Yes (this code only used for 1966-67) 10 bolt Eaton
EZ 2.73 No (this code only used for 1968-69) 10 bolt Eaton
FD 2.29 No (this code only used for 1968) 12 bolt  
FE 2.29 Yes (this code only used for 1968) 12 bolt  
FT 2.56 No (this code only used for 1968-69) 10 bolt  
FU 2.56 Yes (this code only used for 1969)  
FV 2.56 Yes (this code only used for 1968-69) 12 bolt  
FW 2.56 Yes (this code only used for 1968-69) 12 bolt  
FX 2.56 Yes (this code only used for 1968-69) 12 bolt  
G 3.07 No (this code only used for 1967) 12 bolt Detroit gear & axle
GA 3.07 No (this code only used for 1966-68) 12 bolt Detroit gear & axle
GB 2.73 No (this code only used for 1967) 12 bolt, Metallic brakes Detroit gear & axle
GC 2.73 Yes (this code only used for 1967) 12 bolt, Metallic brakes Detroit gear & axle
GD 3.07 No (this code only used for 1967) 12 bolt, Taxi Detroit gear & axle
GE 3.31 No (this code only used for 1967) 12 bolt, Taxi Detroit gear & axle
GF 3.07 Yes (this code only used for 1966-68) 12 bolt Detroit gear & axle
GG 3.07 Yes (this code only used for 1966-67) 12 bolt, Metallic brakes Detroit gear & axle
GH 3.31 Yes (this code only used for 1968-69) 12 bolt, H.D. brakes Detroit gear & axle
GI 3.31 No (this code only used for 1966-68) 12 bolt Detroit gear & axle
GJ 3.31 Yes (this code only used for 1966-68) 12 bolt Detroit gear & axle
GK 2.73 No (this code only used for 1967-69) 12 bolt Detroit gear & axle
GL 3.07 No (this code only used for 1966-67) 12 bolt, Metallic brakes Detroit gear & axle
GM 2.73 Yes (this code only used for 1967-69) 12 bolt Detroit gear & axle
GN 3.31 No (this code only used for 1966-67) 12 bolt, Metallic brakes Detroit gear & axle
GO 3.31 Yes (this code only used for 1966-67) 12 bolt, Metallic brakes Detroit gear & axle
GP 3.55 No (this code only used for 1966-69) 12 bolt Detroit gear & axle
GQ 3.08 No (this code only used for 1966-69) 10 bolt Detroit gear & axle
GR 3.08 Yes (this code only used for 1966-689 10 bolt Detroit gear & axle
GS 3.08 No (this code only used for 1966) 10 bolt, Metallic brakes Detroit gear & axle
GS 3.07 No (this code only used for 1968-69) 12 bolt, Metallic brakes Detroit gear & axle
GT 3.08 Yes (this code only used for 1966) 10 bolt, Metallic brakes Detroit gear & axle
GT 3.07 Yes (this code only used for 1968-69) 12 bolt, H.D. brakes Detroit gear & axle
GU 3.36 Yes (this code only used for 1966)-69 10 bolt, Detroit gear & axle
GV 3.36 No (this code only used for 1966-67) 10 bolt, Metallic brakes Detroit gear & axle
GV 3.55 Yes (this code only used for 1968-69) 12 bolt, H.D. brakes Detroit gear & axle
GW 3.36 Yes (this code only used for 1966-67) 10 bolt, Metallic brakes Detroit gear & axle
GW 3.07 Yes (this code only used for 1968-69) 12 bolt, H.D. brakes Detroit gear & axle
GX 3.55 Yes (this code only used for 1966-69) 10 bolt, Detroit gear & axle
GY 3.55 No (this code only used for 1966-67) 10 bolt, Metallic brakes Detroit gear & axle
GZ 3.55 No (this code only used for 1966-67) 10 bolt Detroit gear & axle


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1970

Code Ratio Posi? Special notes Build plant
CDA 3.08 No 10 bolt  
CDD 3.31 No 12 bolt  
CDE 3.31 No 12 bolt  
CDF 3.07 Yes 12 bolt  
CDG 3.08 Yes 10 bolt  
CDH 3.31 Yes 12 bolt  
CDX 2.73 Yes 10 bolt  
CDY 2.73 Yes 10 bolt  
CDZ 2.73 No 10 bolt  
CE3 2.73 No 10 bolt  
CEA 2.56 No 10 bolt  
CED 2.56 Yes 10 bolt  
CEM 3.07 No 12 bolt  
CEN 3.07 No 12 bolt  
CES 3.08 No 10 bolt  
CET 3.08 Yes 10 bolt  
CEU 3.36 No 10 bolt  
CEZ 2.73 No 10 bolt  
CFW 2.56 No 10 bolt  
CFX 2.56 Yes 10 bolt  
CGH 3.31 Yes 12 bolt  
CGK 2.73 No 10 bolt  
CGM 2.73 Yes 10 bolt  
CGU 3.36 Yes 10 bolt  
CGW 3.07 Yes 12 bolt  
CLJ 2.56 Yes 10 bolt  
CLK 2.73 Yes 10 bolt  
CLN 3.07 Yes 12 bolt  
CMY 2.56 No 10 bolt  
CNA 2.73 No 10 bolt  
CND 3.07 No 12 bolt  
CWK 3.07 No 12 bolt  
CWP 3.07 Yes 12 bolt  
CWY 3.31 No 12 bolt  
CWZ 3.31 Yes 12 bolt  


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