1964 and later A Body and 1965 Big Car Axle ID codes are stamped here
1965-1967 Nodular iron cases are stamped with a large “N” as shown
1964 and earlier Big Car carriers are stamped as shown with axle and anti-spin indicators.
Pontiac Differential Codes
| Pontiac Differential Codes | |||||
| Year | Model | Rear Ratio | Tooth Count | Std Code | Posl Code |
| 1965-1966 | Tempest-GTO | 3.08 | 40/13 | WE | YE |
| 1965-1966 | Tempest-GTO | 3.08 | 40/13 | XE | ZE |
| 1965-1966 | Tempest-GTO | 3.23 | 42/13 | WF | YF |
| 1965-1966 | Tempest-GTO | 3.23 | 42/13 | XF | ZF |
| 1965-1966 | Tempest-GTO | 3.36 | 37/11 | WG | YG |
| 1965-1966 | Tempest-GTO | 3.36 | 37/11 | XG | ZG |
| 1965-1966 | Tempest-GTO | 3.55 | 39/11 | WH | YH |
| 1965-1966 | Tempest-GTO | 3.55 | 39/11 | XH | ZH |
| 1965-1966 | Tempest-GTO | 3.9 | 39/10 | - - | ZK |
| 1965-1966 | Tempest-GTO | 4.33 | 39/9 | - - | ZL |
| 1966 | Tempest-GTO | 2.41 | 41/17 | UB | VB |
| 1966 | Tempest-GTO | 2.56 | 41/16 | UC | VC |
| 1966 | Tempest-GTO | 2.73 | 41/15 | UD | VD |
| 1966 | Tempest-GTO | 2.93 | 41/14 | UE | VE |
| 1966 | Tempest-GTO | 3.08 | 40/13 | UF | VF |
| 1966 | Tempest-GTO | 3.23 | 42/13 | UG | VG |
| 1966 | Tempest-GTO | 3.42 | 41/12 | UH | VH |
| 1966 | Tempest-GTO | 3.73 | 41/11 | UK | VK |
| 1966 | Tempest-GTO | 4.11 | 37/9 | UM | VM |
| 1967 | Tempest-GTO | 2.29 | 39/17 | UA | VA |
| 1967 | Tempest-GTO | 2.41 | 41/17 | UB | VB |
| 1967 | Tempest-GTO | 2.56 | 41/16 | UC | VC |
| 1967 | Tempest-GTO | 2.73 | 41/15 | UD | VD |
| 1967 | Tempest-GTO | 2.93 | 41/14 | UE | VE |
| 1967 | Tempest-GTO | 3.08 | 40/13 | UF | VF |
| 1967 | Tempest-GTO | 3.23 | 42/13 | UG | VG |
| 1967 | Tempest-GTO | 3.42 | 41/12 | UH | VH |
| 1967 | Tempest-GTO | 3.55 | 39/11 | - - | VJ |
| 1967 | Tempest-GTO | 3.73 | 41/11 | - - | VK |
| 1967 | Tempest-GTO | 4.11 | 37/9 | - - | VM |
| 1967 | Tempest-GTO | 2.56 | 41/16 | XB | ZB |
| 1967 | Tempest-GTO | 2.78 | 39/14 | XC | ZC |
| 1967 | Tempest-GTO | 2.93 | 41/14 | XD | ZD |
| 1967 | Tempest-GTO | 3.08 | 40/13 | XE | ZE |
| 1967 | Tempest-GTO | 3.23 | 42/13 | XF | ZF |
| 1967 | Tempest-GTO | 3.36 | 37/11 | XG | ZM 4 pinion |
| 1967 | Tempest-GTO | 3.55 | 39/11 | XH | ZN 4 pinion |
| 1967 | Tempest-GTO | 3.9 | 39/10 | - - | ZP 4 pinion |
| 1967 | Tempest-GTO | 4.33 | 39/9 | - - | ZR 4 pinion |
| 1967 | Tempest-GTO | 2.56 | 41/16 | WB | YB |
| 1967 | Tempest-GTO | 2.78 | 39/14 | WC | YC |
| 1967 | Tempest-GTO | 2.93 | 41/14 | WD | YD |
| 1967 | Tempest-GTO | 3.08 | 40/13 | WE | YE |
| 1967 | Tempest-GTO | 3.23 | 42/13 | WF | YF |
| 1967 | Tempest-GTO | 3.36 | 37/11 | WG | YG |
| 1967 | Tempest-GTO | 3.55 | 39/11 | WH | YH |
| 1967 | Tempest-GTO | 3.9 | 39/10 | WK | YK |
| 1967 | Tempest-GTO | 4.33 | 39/9 | - - | YL |
| 1968 | Tempest-GTO | 2.29 | 39/17 | UA | VA |
| 1968 | Tempest-GTO | 2.41 | 41/17 | UB | VB |
| 1968 | Tempest-GTO | 2.56 | 41/16 | UC | VC |
| 1968 | Tempest-GTO | 2.73 | 41/15 | UD | VD |
| 1968 | Tempest-GTO | 2.93 | 41/14 | UE | VE |
| 1968 | Tempest-GTO | 3.08 | 40/13 | UF | VF |
| 1968 | Tempest-GTO | 3.23 | 42/13 | UG | VG |
| 1968 | Tempest-GTO | 3.42 | 41/12 | UH | VH |
| 1968 | Tempest-GTO | 3.55 | 39/11 | - - | VJ |
| 1968 | Tempest-GTO | 3.73 | 41/11 | - - | VK |
| 1968 | Big Pontiac | 4.11 | 37/9 | - - | VM |
| 1968 | Firebird | 2.56 | 41/16 | XB | ZB |
| 1968 | Firebird | 2.78 | 39/14 | XC | ZC |
| 1968 | Firebird | 2.93 | 41/14 | XD | ZD |
| 1968 | Firebird | 3.08 | 40/13 | XE | ZE |
| 1968 | Firebird | 3.23 | 42/13 | XF | ZF |
| 1968 | Firebird | 3.36 | 37/11 | XG | ZM 4 pinion |
| 1968 | Firebird | 3.55 | 39/11 | XH | ZN 4 pinion |
| 1968 | Firebird | 3.9 | 39/10 | - - | ZP 4 pinion |
| 1968 | Firebird | 4.33 | 39/9 | - - | ZR 4 pinion |
| 1968 | Tempest - GTO | 2.56 | 41/16 | WB | YB |
| 1968 | Tempest - GTO | 2.78 | 39/14 | WC | YC |
| 1968 | Tempest - GTO | 2.93 | 41/14 | WD | YD |
| 1968 | Tempest - GTO | 3.08 | 40/13 | WE | YE |
| 1968 | Tempest - GTO | 3.23 | 42/13 | WF | YF |
| 1968 | Tempest - GTO | 3.36 | 37/11 | WG | ZG 4 pinion |
| 1968 | Tempest - GTO | 3.55 | 39/11 | WH | ZH 4 pinion |
| 1968 | Tempest - GTO | 3.9 | 39/10 | WK | ZK 4 pinion |
| 1968 | Tempest - GTO | 4.33 | 39/9 | - - | ZL 4 pinion |
| 1969 | Big Pontiac | 2.29 | 39/17 | UA | VA |
| 1969 | Big Pontiac | 2.41 | 41/17 | UB | VB |
| 1969 | Big Pontiac | 2.56 | 41/16 | UC | VC |
| 1969 | Big Pontiac | 2.73 | 41/15 | UD | VD |
| 1969 | Big Pontiac | 2.93 | 41/14 | UE | VE |
| 1969 | Big Pontiac | 3.08 | 40/13 | UF | VF |
| 1969 | Big Pontiac | 3.23 | 42/13 | UG | VG |
| 1969 | Big Pontiac | 3.42 | 41/12 | UH | VH |
| 1969 | Big Pontiac | 3.55 | 39/11 | - - | VJ |
| 1969 | Big Pontiac | 3.73 | 41/11 | - - | VK |
| 1969 | Big Pontiac | 4.11 | 37/9 | - - | VM |
| 1969 | Firebird | 2.56 | 41/16 | YB | ZB |
| 1969 | Firebird | 2.78 | 39/14 | YC | ZC |
| 1969 | Firebird | 2.93 | 41/14 | YD | ZD |
| 1969 | Firebird | 3.08 | 40/13 | YE | ZE |
| 1969 | Firebird | 3.23 | 42/13 | YF | ZF |
| 1969 | Firebird | 3.36 | 37/11 | YG | ZG |
| 1969 | Firebird | 3.55 | 39/11 | YH | ZH |
| 1969 | Firebird | 3.9 | 39/10 | - - | ZK 4 pinion |
| 1969 | Firebird | 4.33 | 39/9 | - - | ZM 4 pinion |
| 1969 | Grand Prix | 2.93 | 41/14 | 2D reg duty - 4D med duty 4 pinion | 5D med duty 4 pinion |
| 1969 | Grand Prix | 3.08 | 40/13 | ZE reg duty - 4E med duty 4 pinion | 5E med duty 4 pinion |
| 1969 | Grand Prix | 3.23 | 42/13 | ZF reg duty - 4F med duty 4 pinion | 5F med duty 4 pinion |
| 1969 | Grand Prix | 3.36 | 37/11 | 4G med duty 4 pinion | 7G HD 4 pinion |
| 1969 | Grand Prix | 3.55 | 39/11 | 4H med duty 4 pinion | 7H HD 4 pinion |
| 1969 | Grand Prix | 3.9 | 39/10 | - - | 7K HD 4 pinion |
| 1969 | Tempest - GTO | 2.56 | 41/16 | WB | XB |
| 1969 | Tempest - GTO | 2.78 | 39/14 | WC | XC |
| 1969 | Tempest - GTO | 2.93 | 41/14 | WD | XD |
| 1969 | Tempest - GTO | 3.08 | 40/13 | WE | XE |
| 1969 | Tempest - GTO | 3.23 | 42/13 | WF | XF |
| 1969 | Tempest - GTO | 3.36 | 37/11 | WG | XG 4 pinion |
| 1969 | Tempest - GTO | 3.55 | 39/11 | WH | XH 4 pinion |
| 1969 | Tempest - GTO | 3.9 | 39/10 | WK | XK 4 pinion |
| 1969 | Tempest - GTO | 4.33 | 39/9 | - - | XL 4 pinion |
| 1970 | Big Pontiac | 2.41 | 41/17 | UB | VB |
| 1970 | Big Pontiac | 2.56 | 41/16 | UC | VC |
| 1970 | Big Pontiac | 2.73 | 41/15 | UD | VD |
| 1970 | Big Pontiac | 2.93 | 41/14 | UE | VE |
| 1970 | Big Pontiac | 3.23 | 42/13 | UG | VG |
| 1970 | Big Pontiac | 3.42 | 41/12 | UH | VH |
| 1970 | Firebird | 2.73 | 41/15 | CRX | CRY |
| 1970 | Firebird | 3.08 | 37/12 | COE | COF |
| 1970 | Firebird | 3.07 12 bolt | 43/14 | COS | COT |
| 1970 | Firebird | 3.36 | 37/11 | COK | COL |
| 1970 | Firebird | 3.31 12 bolt | 43/13 | COU | COV |
| 1970 | Firebird | 3.55 12 bolt | 39/11 | COW | COX |
| 1970 | Firebird | 3.73 12 bolt | 41/11 | - - | COZ |
| 1970 | Grand Prix | 2.78 | 39/14 | AC | BC |
| 1970 | Grand Prix | 2.93 | 41/14 | AD | BD 4 pinion |
| 1970 | Grand Prix | 3.07 12 bolt | 43/14 | WT | XT |
| 1970 | Grand Prix | 3.23 | 42/13 | AF | BF 4 pinion |
| 1970 | Grand Prix | 3.31 12 bolt | 43/13 | WU | XU |
| 1970 | Grand Prix | 3.55 12 bolt | 39/11 | WV | XV |
| 1970 | GTO-GP | 2.56 | 41/16 | LJ | LY |
| 1970 | GTO-GP | 2.73 | 41/15 | LE | LS |
| 1970 | GTO-GP | 3.07 | 43/14 | LD | LR |
| 1970 | GTO-GP | 3.31 | 43/13 | LG | LV |
| 1970 | GTO-GP | 3.55 | 39/11 | LF | LQ |
| 1970 | GTO-GP | 3.73 | 41/11 | - - | LU |
| 1970 | Tempest - GTO | 2.56 | 41/16 | WB | XB |
| 1970 | Tempest - GTO | 2.78 | 39/14 | WC | XC |
| 1970 | Tempest - GTO | 3.07 12 bolt | 43/14 | WT | XT |
| 1970 | Tempest - GTO | 3.08 | 40/13 | WE | XE |
| 1970 | Tempest - GTO | 3.23 | 42/13 | WF | XF |
| 1970 | Tempest - GTO | 3.31 12 bolt | 43/13 | WU | XU |
| 1970 | Tempest - GTO | 3.55 | 39/11 | WH | XH 4 pinion |
| 1970 | Tempest - GTO | 3.55 12 bolt | 39/11 | WV | XV |
| 1970 | Tempest - GTO | 3.9 | 39/10 | - - | XK 4 pinion |
| 1970 | Tempest - GTO | 4.33 | 39/9 | - - | XM 4 pinion |
| 1971 | A-body | 2.56 | 41/16 | WB | XB |
| 1971 | A-body | 2.78 | 39/14 | WC | XC |
| 1971 | A-body | 3.07 12 bolt | 43/14 | WT | XT |
| 1971 | A-body | 3.08 | 40/13 | WE | XE |
| 1971 | A-body | 3.23 | 42/13 | WF | XF |
| 1971 | A-body | 3.31 12 bolt | 43/13 | WU | XU |
| 1971 | A-body | 3.55 | 39/11 | WH | XH |
| 1971 | A-body | 3.55 12 bolt | 39/11 | WV | XV |
| 1971 | A-body | 3.9 | 39/10 | - - | XK 4 pinion |
| 1971 | A-body | 4.33 | 39/9 | - - | XM 4 pinion |
| 1971 | Big Pontiac | 2.56 | 41/16 | UC | VC |
| 1971 | Big Pontiac | 2.73 | 41/15 | UD | VD |
| 1971 | Big Pontiac | 2.73 | 41/15 | YD | ZD |
| 1971 | Big Pontiac | 3.08 | 40/13 | NA | NP |
| 1971 | Big Pontiac | 3.08 | 40/13 | YF | ZF |
| 1971 | Big Pontiac | 3.08 | 40/13 | UF | VF |
| 1971 | Big Pontiac | 3.08 | 40/13 | WP | XJ |
| 1971 | Big Pontiac | 3.23 | 42/13 | UG | VG |
| 1971 | Big Pontiac | 3.23 | 42/13 | WA | XL |
| 1971 | Big Pontiac | 3.23 | 42/13 | YG | ZG |
| 1971 | Big Pontiac | 3.42 | 41/12 | NH | NN |
| 1971 | Big Pontiac | 3.42 | 41/12 | UH | VH |
| 1971 | Big Pontiac | 3.42 | 41/12 | WJ | X3 |
| 1971 | Big Pontiac | 3.42 | 41/12 | YH | ZH |
| 1971 | Firebird | 2.73 | 41/15 | GZ | CA |
| 1971 | Firebird | 3.08 | 37/12 | GX | GY |
| 1971 | Firebird | 3.42 | 41/12 | CK | CJ |
| 1971 | Firebird | 3.73 | 41/11 | - - | CG |
| 1971 | Firebird | 4.1 | 41/10 | - - | CB |
| 1971 | GP | 2.78 | 39/14 | AC | BC |
| 1971 | GP | 3.07 12 bolt | 43/14 | WT | XT |
| 1971 | GP | 3.08 | 40/13 | AE | BE |
| 1971 | GP | 3.23 | 42/13 | AF | BF |
| 1971 | GP | 3.31 12 bolt | 43/13 | WU | XU |
| 1971 | GP | 3.55 12 bolt | 39/11 | WV | XV |
| 1971 | Ventura II | 2.56 | 41/16 | GJ | GK |
| 1971 | Ventura II | 3.08 | 40/13 | GR | GS |
| 1972 | A and G | 2.56 | 41/16 | WB | XB |
| 1972 | A and G | 2.78 | 39/14 | WC | XC |
| 1972 | A and G | 3.07 12 bolt | 43/14 | WT | XT |
| 1972 | A and G | 3.08 | 40/13 | WE | XE |
| 1972 | A and G | 3.08 | 40/13 | AE | BE |
| 1972 | A and G | 3.23 | 42/13 | WF | XF |
| 1972 | A and G | 3.23 | 42/13 | AF | BF |
| 1972 | A and G | 3.31 12 bolt | 43/13 | WU | XU |
| 1972 | A and G | 3.55 | 39/11 | WH | XH |
| 1972 | A and G | 3.55 12 bolt | 39/11 | WV | XV |
| 1972 | Big Pontiac | 2.56 | 41/16 | UC | VC |
| 1972 | Big Pontiac | 2.73 | 41/15 | UD | VD |
| 1972 | Big Pontiac | 2.73 | 41/15 | NK | NT |
| 1972 | Big Pontiac | 2.73 | 41/15 | YD | ZD |
| 1972 | Big Pontiac | 3.08 | 40/13 | NA | NP |
| 1972 | Big Pontiac | 3.08 | 40/13 | YF | ZF |
| 1972 | Big Pontiac | 3.08 | 40/13 | UF | VF |
| 1972 | Big Pontiac | 3.08 | 40/13 | WP | XJ |
| 1972 | Big Pontiac | 3.23 | 42/13 | UG | VG |
| 1972 | Big Pontiac | 3.23 | 42/13 | NJ | NR |
| 1972 | Big Pontiac | 3.23 | 42/13 | WA | XL |
| 1972 | Big Pontiac | 3.23 | 42/13 | YG | ZG |
| 1972 | Big Pontiac | 3.42 | 41/12 | YH | ZH |
| 1972 | Firebird | 2.73 | 41/15 | GZ | CA |
| 1972 | Firebird | 3.08 | 37/12 | GX | GY |
| 1972 | Firebird | 3.42 | 41/12 | CK | CJ |
| 1972 | Firebird | 3.73 | 41/11 | - - | CG |
| 1972 | X body | 2.56 | 41/16 | GJ | GK |
| 1972 | X body | 3.08 | 40/13 | GR | GS |
| 1973 | A and G | 2.73 | 41/15 | AC | CC |
| 1973 | A and G | 2.73 | 41/15 | WA | XA |
| 1973 | A and G | 3.08 | 40/13 | AD | CD |
| 1973 | A and G | 3.08 | 40/13 | WC | XC |
| 1973 | A and G | 2.93 | 41/14 | AF | CF |
| 1973 | A and G | 3.23 | 42/13 | AE | CE |
| 1973 | A and G | 3.23 | 43/13 | WD | XD |
| 1973 | A and G | 3.42 | 41/12 | AJ | CJ |
| 1973 | A and G | 3.42 | 41/12 | WE | XE |
| 1973 | Big Pontiac | 2.56 | 41/16 | UC | VC |
| 1973 | Big Pontiac | 2.73 | 41/15 | UD | VD |
| 1973 | Big Pontiac | 2.73 | 41/15 | NK | NT |
| 1973 | Big Pontiac | 2.73 | 41/15 | YD | ZD |
| 1973 | Big Pontiac | 3.08 | 40/13 | NA | NP |
| 1973 | Big Pontiac | 3.08 | 40/13 | YF | ZF |
| 1973 | Big Pontiac | 3.08 | 40/13 | UF | VF |
| 1973 | Big Pontiac | 3.08 | 40/13 | WP | XJ |
| 1973 | Big Pontiac | 3.23 | 42/13 | UG | VG |
| 1973 | Big Pontiac | 3.23 | 42/13 | NJ | NR |
| 1973 | Big Pontiac | 3.23 | 42/13 | WA | XL |
| 1973 | Big Pontiac | 3.23 | 42/13 | YG | ZG |
| 1973 | Big Pontiac | 3.42 | 41/12 | YH | ZH |
| 1973 | Firebird | 2.73 | 41/15 | GZ | CA |
| 1973 | Firebird | 3.08 | 37/12 | GX | GY |
| 1973 | Firebird | 3.42 | 41/12 | CL | CM |
| 1973 | X body | 2.73 | 41/15 | JG | JV |
| 1973 | X body | 3.08 | 37/12 | JL | JW |
| 1974 | A and G | 2.73 | 41/15 | AC | CC |
| 1974 | A and G | 2.73 | 41/15 | WA | XA |
| 1974 | A and G | 3.08 | 40/13 | AD | CD |
| 1974 | A and G | 3.08 | 40/13 | WC | XC |
| 1974 | A and G | 2.93 | 41/14 | AF | CF |
| 1974 | A and G | 2.93 | 41/14 | WB | XB |
| 1974 | A and G | 3.23 | 42/13 | AE | CE |
| 1974 | A and G | 3.23 | 43/13 | WD | XD |
| 1974 | A and G | 3.42 | 41/12 | WE | XE |
| 1974 | Big Pontiac | 2.73 | 41/15 | UA | VA |
| 1974 | Big Pontiac | 2.73 | 41/15 | UJ | VJ |
| 1974 | Big Pontiac | 2.73 | 41/15 | YA | ZA |
| 1974 | Big Pontiac | 3.08 | 40/13 | KC | LC |
| 1974 | Big Pontiac | 3.08 | 40/13 | UC | VC |
| 1974 | Big Pontiac | 3.08 | 40/13 | UL | VL |
| 1974 | Big Pontiac | 3.08 | 40/13 | YC | ZA |
| 1974 | Big Pontiac | 3.23 | 42/13 | YD | ZD |
| 1974 | Big Pontiac | 3.23 | 42/13 | UD | VD |
| 1974 | Big Pontiac | 3.23 | 42/13 | UM | VM |
| 1974 | Big Pontiac | 3.42 | 41/12 | UE | VE |
| 1974 | Big Pontiac | 3.42 | 41/12 | UN | VN |
| 1974 | Big Pontiac | 3.42 | 41/12 | YE | ZE |
| 1974 | Firebird | 2.73 | 41/15 | GZ | CA |
| 1974 | Firebird | 3.08 | 37/12 | GX | GY |
| 1974 | Firebird | 3.42 | 41/12 | CL | CM |
| 1974 | X body | 2.73 | 41/15 | JA | JM |
| 1974 | X body | 3.08 | 40/13 | JB | JN |
| 1975 | A and G | 2.73 | 41/15 | AC | CC |
| 1975 | A and G | 2.73 | 41/15 | WL | XL |
| 1975 | A and G | 3.08 | 40/13 | AD | CD |
| 1975 | A and G | 3.08 | 40/13 | AD | CD |
| 1975 | A and G | 2.93 | 41/14 | AF | CF |
| 1975 | A and G | 2.93 | 41/14 | WB | XB |
| 1975 | A and G | 2.93 | 41/14 | WM | XM |
| 1975 | Big Pontiac | 2.56 | 41/16 | KF | LF |
| 1975 | Big Pontiac | 2.73 | 41/15 | UA | VA |
| 1975 | Big Pontiac | 2.93 | 41/14 | UJ | VJ |
| 1975 | Big Pontiac | 2.93 | 41/14 | UB | VB |
| 1975 | Big Pontiac | 2.73 | 41/15 | YA | ZA |
| 1975 | Big Pontiac | 3.23 | 42/13 | YD | ZD |
| 1975 | Big Pontiac | 3.23 | 42/13 | UD | VD |
| 1975 | Firebird | 2.73 | 41/15 | PA | PU |
| 1975 | Firebird | 3.08 | 40/13 | PC | PW |
| 1975 | Firebird | 2.56 | 41/16 | PG | PT |
| 1975 | X body | 2.56 | 41/16 | GA | JU |
| 1975 | X body | 2.73 | 41/15 | GB | JV |
| 1975 | X body | 3.08 | 40/13 | GD | JX |
