| Casting Number | Make | Year | CID |
| 1970 | Chevrolet | 1964-1967 | 292 |
| 2135412 | GMC | 1946-1954 | 248,270 |
| 2193980 | GMC | 1952-1954 | 302 |
| 2324003 | GMC | 1955-1963 | 270 |
| 2324004 | GMC | 1955-1962 | 302 |
| 2404929 | GMC | 1955-1963 | 270 |
| 2192402 | GMC | Military | 302 |
| 289890 | Chevrolet | 1963-1977 | 292 |
| 328575 | Chev/Buick/Olds/Pontiac | 1968-1984 | 250 |
| 328576 | Chev/Buick/Pontiac | 1968-1976 | 250 |
| 328880 | Chevrolet | 1963-1977 | 292 |
| 329990 | Chevrolet | 1963-1977 | 292 |
| 358825 | Chevrolet | 1966-1976 | 250 |
| 3629703 | Chevrolet | 1950-1952 | 235 |
| 366855 | Chev/Buick/Olds/Pontiac | 1966-1984 | 250 |
| 3692703 | Chevrolet | 1950-1952 | 235 |
| 3692708 | Chevrolet | 1950-1952 | 235 |
| 3692713 | Chevrolet | 1950-1952 | 235 |
| 3693374 | Chevrolet | 1942-1949 | 235 |
| 37001481 | Chevrolet | 1953-1955 | 235 |
| 3701946 | Chevrolet | 1953 | 235 |
| 3703414 | Chevrolet | 1954-1956 | 261 |
| 3733340 | Chevrolet | 1955-1957 | 261 |
| 3733813 | Chevrolet | 1958 | 261 |
| 3733946 | Chevrolet | 1954-1955 | 235 |
| 3733949 | Chevrolet | 1953-1955 | 235 |
| 3733950 | Chevrolet | 1954-1955 | 261 |
| 3737012 | Chevrolet | 1955-1957 | 261 |
| 3738307 | Chevrolet | 1958-1962 | 235 |
| 3738365 | Chevrolet | 1960-1962 | 261 |
| 3738476 | Chevrolet | 1958-1962 | 235 |
| 3738813 | Chevrolet | 1955-1963 | 261 |
| 3739365 | Chevrolet | 1958-1962 | 261 |
| 3739716 | Chevrolet | 1958-1962 | 235 |
| 3759365 | Chevrolet | 1959 | 261 |
| 3764476 | Chevrolet | 1958-1962 | 235 |
| 3769716 | Chevrolet | 1958-1962 | 235 |
| 3769717 | Chevrolet | 1959-1962 | 261 |
| 3769925 | Chevrolet | 1958-1962 | 261 |
| 3773949 | Chevrolet | 1954 | 235 |
| 3782856 | Chevrolet | 1962-1967 | 194 |
| 3782858 | Chevrolet | 1962-1967 | 194 |
| 378307 | Chevrolet | 1960-1962 | 235 |
| 3783949 | Chevrolet | 1953-1954 | 235 |
| 3788378 | Chevrolet | 1962-1974 | 292 |
| 3788406 | Chevrolet | 1962-1969 | 230 |
| 3788514 | Chevrolet | 1962-1970 | 153 |
| 3788813 | Chevrolet | 1955-1959 | 261 |
| 3789404 | Chevrolet | 1963-1976 | 292 |
| 3789412 | Chevrolet | 1963-1966 | 292 |
| 3789716 | Chevrolet | 1963-1972 | 292 |
| 3792852 | GMC | 1962-1966 | 194 |
| 3792858 | Chevrolet | 1962-1967 | 194 |
| 3821970 | GMC | 1967-1972 | 292 |
| 3833057 | Chevrolet | 1962-1970 | 191 |
| 3833067 | Chevrolet | 1963-1970 | 194 |
| 3833340 | Chevrolet | 1955-1957 | 261 |
| 383340 | Chevrolet | 1955-1957 | 261 |
| 3835253 | Chevrolet | 1942-1953 | 216 |
| 3835309 | Chevrolet | 1942-1949 | 235 |
| 3835335 | Chevrolet | 1942-1949 | 235 |
| 3835353 | Chevrolet | 1948-1952 | 216 |
| 3835363 | Chevrolet | 1954 | 235 |
| 3835374 | Chevrolet | 1942-1949 | 235 |
| 3835491 | Chevrolet | 1954 | 235 |
| 3835497 | Chevrolet | 1942-1953 | 216 |
| 3835527 | Chevrolet | 1951 | 216 |
| 3835692 | Chevrolet | 1950-1952 | 235 |
| 3835794 | Chevrolet | 1942-1953 | 216 |
| 3835846 | Chevrolet | 1953 | 235 |
| 3835849 | Chevrolet | 1942-1953 | 216 |
| 3835894 | Chevrolet | 1953 | 216 |
| 3835911 | Chevrolet | 1953-1955 | 235 |
| 3835917 | Chevrolet | 1954-1955 | 235 |
| 3835946 | Chevrolet | 1953 | 235 |
| 3835949 | Chevrolet | 1954 | 235 |
| 3836012 | Chevrolet | 1955-1957 | 261 |
| 3836223 | Chevrolet | 1955-1957 | 235 |
| 3836233 | Chevrolet | 1955-1957 | 235 |
| 3836340 | Chevrolet | 1955-1958 | 261 |
| 3836386 | Chevrolet | 1955-1957 | 235 |
| 3837004 | Chevrolet | 1955-1957 | 235-261 |
| 3837012 | Chevrolet | 1955-1957 | 261 |
| 3843363 | Chevrolet | 1953-1955 | 235 |
| 3850817 | Chevrolet | 1962-1978 | 230-250 |
| 3851656 | Chevrolet | 1963-1972 | 292 |
| 3851659 | Chevrolet | 1963-1976 | 292 |
| 3851859 | Chevrolet | 1963-1972 | 292 |
| 3854036 | Chevrolet/Olds/Pontiac | 1962-1976 | 230-250 |
| 3855914 | Chevrolet | 1963-1966 | 292 |
| 3855987 | Chevrolet | 1963-1971 | 292 |
| 3855991 | Chevrolet | 1963-1970 | 230 |
| 3856233 | Chevrolet | 1955 | 235 |
| 3858190 | Chevrolet | 1954-1955 | 235 |
| 3877178 | Buick/Olds/Chev/Pont/GMC | 1962-1978 | 230-250 |
| 3879875 | Chevrolet | 1962-1970 | 194 |
| 3886061 | Chevrolet | 1963-1966 | 292 |
| 3890011 | Buick/Chev/Olds/Pontiac | 1968-1972 | 250 |
| 3890013 | Chevrolet | 1968-1972 | 250 |
| 3892858 | Chevrolet | 1964-1967 | 194 |
| 389770 | Chevrolet | 1942-1951 | 216 |
| 3897702 | Chevrolet | 1942-1953 | 216 |
| 3921770 | Chevrolet | 1966-1976 | 292 |
| 3921967 | Chevrolet | 1964-1969 | 230 |
| 3921968 | Chevrolet | 1964-1976 | 230-150 |
| 3921970 | Chevrolet | 1963-1976 | 292 |
| 828575 | Chevrolet | 1972-1977 | 250 |
| 837751 | Chevrolet | 1942-1949 | 235 |
| 839770 | Chevrolet | 1942-1953 | 216 |
| 8397715 | Chevrolet | 1942-1949 | 235 |
| 839910 | Chevrolet | 1942-1951 | 216 |
| 839931 | Chevrolet | 1942-1949 | 235 |
| 8994256 | Chevrolet | 1964-1977 | 292 |
| 9890043 | Pontiac | 1968-1969 | 250 |
Mechanical
Casting Numbers
Thursday, February 11th, 2010
Venting the Differential
Thursday, February 11th, 2010
Sometimes overlooked by mechanics and restorers is a small vent in the rear axle housing. This part is necessary to keep internal pressure equal to the outside atmosphere. Thus, as the internal temperature of the differential warms during use, any expanding heated air is vented and no pressure occurs. This saves wheel and pinion seals from leaking.
Check for this vent in your truck. From years of abuse many vent assemblies are missing. A sliding log chain wrapped around the axle housing for pulling is a way many vent assemblies were accidentally removed. The owner usually didn’t know the damage has been done or that a vent ever existed. Now, the small hole that once held the vent assembly is able to take in water. This is certainly not good for the internal differential parts.
1946-1972 Ring and Pinion
Thursday, February 11th, 2010
One series of the famous “drop out” GM differentials was used between 1946 and 1972 on 3/4 and 1 tons. The complete assembly (often called a pumpkin) will interchange during these years with no alteration.
The highest gearing in this series is the 4.10 ratio and is found in most 1967-72 3/4 tons with automatic transmissions. Therefore, those “low gear blues” often associated with 3/4 and 1 tons during the late 1940′s and 1950′s can be greatly improved with no visible exterior changes. Originally these older trucks had a ratio of 4.57 in the 3/4 tons and 5.14 in the 1 tons.
Once a 4.10 pumpkin is located (usually in a local wrecking yard) it is a basic interchange requiring little more than new gaskets and gear grease. Your truck’s personality is now changed!
This interchange will fit perfectly if the “complete” pumpkin is used. The 1963-1972 carrier is necessary and it will be part of this total assembly. The change-over will not work if you only use the ring and pinion.
The only negative to this changeover is if you are hauling a ton of gravel up a mountain road with the original smaller six cylinder!! In this example a lower geared differential is best.
