Mopar A833 Manual Transmission Identification and Gear Ratios
There are two basic types of the New Process A-833 transmissions used by Mopar muscle cars. They are easily identified by the length of the tailshaft.
Short tailshaft transmissions are 23 3/16″ inches from where they mount to the bellhousing to the end of the transmission and are found in the smaller A-body and F-body cars.
Long tailshaft transmissions are 27″ inches from where they mount to the bellhousing to the end of the transmission and are found in the mid size and larger B-body, E-body and C-body cars as well as light trucks and vans into the 80′s.
| Transmission | 1st | 2nd | 3rd | 4th | Notes |
| 1964 – 1966 A-body | 3.09:1 | 1.92:1 | 1.40:1 | 1:1 | Slant Six and Small Block engines. These transmissions had a short tailshaft and used a small 4.35″ input bearing retainer size. |
| 1964 – 1970 B/RB engine | 2.66:1 | 1.91:1 | 1.39:1 | 1:1 | These transmissions had a long tailshaft with a single forward shifter mounts which is not on the same position as the later 1971-1974 transmissions. This is considered the “close ratio” V8 gearbox. |
| 1966 – 1971 Hemi or 440 Six Pack engine | 2.65:1 | 1.91:1 | 1.39:1 | 1:1 | These transmissions had a long tailshaft with a single forward shifter mounts and a 1 1/8″ thick 18 spline input shaft. These are the heavy duty A-833 transmissions. |
| 1967 – 1974 A-body | 2.66:1 | 1.91:1 | 1.39:1 | 1:1 | These transmissions had a short tailshaft are were the standard four speed offered in V8 A-bodies. |
| 1970 only – Challenger T/A or AAR Cuda w/ 340 Six Pack | 2.47:1 | 1.77:1 | 1.34:1 | 1:1 | These transmissions had a long tailshaft with dual shifter mounts. |
| 1970 – 1974 High Performance | 2.44:1 | 1.91:1 | 1.34:1 | 1:1 | These transmissions had a long tailshaft with dual shifter mounts. |
| 1975 – 1987 Passenger Car Overdrive | 3.09:1 | 1.67:1 | 1:1 | 0.73:1 | These transmissions had a short tailshaft and used the large 5.125″ input bearing retainer size. |
| 1975 – 1987 Truck Overdrive | 3.09:1 | 1.67:1 | 1:1 | 0.71:1 | These transmissions had a long tailshaft with dual shifter mounts and used the large 5.125″ input bearing retainer size. |
| 1981 -1986 Chevy/GM Truck Overdrive | 3.09:1 | 1.67:1 | 1:1 | 0.71:1 | This A-833 used a 10 spline input shaft and had a bolt pattern specific to the GM A833 bellhousing. General Engines designated this transmission code MY6. |
Can the smaller input shaft and bearing retainer be replaced with the larger 5.125” 18 spline ? Im having a hard time finding parts for my 78 D100.