Chrysler A-833 four speed

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History

In 1964, Chrysler released a new four speed transmission built by New Process called the A-833. Production of this transmission continued into the seventies and eventually turned into an three speed plus overdrive offered to economy minded Volare, Aspen, truck, and van buyers. There are two Mopar Action articles on four speeds that should be considered required reading for anyone seeking to learn more about A-833s (back issue: Tech Special 1995). The Mopar Chassis manual also has some good information. What follows here pales in comparsion to the kind of data you'll find in the Mopar Action articles, but it will get you going until you lay your hands on some back issues. A Factory Service Manual (FSM) should be considered essential once you have a four speed and you want to start servicing it.

The New Process A-833 was used in Chrysler passenger cars 1964-80, Dodge trucks 1976-87, and 1981-86 General Motors trucks (GM models may be identified as RPO code MY6 Produced in 2x4 and 4x4 versions. Of course, it'll carry the GM input shaft) There were several different versions of the A-833 produced and several changes that it went through in the fifteen or so years it was in production. Walking up to a pile of A-833s at a swap meet, the most obvious differences are the overall length and the output type (flanged or slip yoke). Chrysler made two different length A-833s. The main gear housings were sized the same, and for many years were the same casting for all models, however, the tailshaft housing differed. The short A-833s were used in A-bodies and F-bodies, the long A-833s were used in B-bodies, C-bodies, and E-bodies. The flanged ball-n-trunion output was used in 1964 and 1965, on A-bodies, B-bodies, and C-bodies alike. In 1966, the slip-yoke output replaced the ball-n-trunion on all A-833s.

A real show stopper on a lot of four speed swaps is the front input bearing retainer diameter. This retainer mates to the big center hole on the bellhousing. For this reason, not all A-833 bellhousings work with all A-833s. The bellhousing must have a matching diameter hole to accept the input bearing retainer (exact match! if the hole in the bellhousing is too big, the transmission will not center properly!). There were three different diameter retainers: a 4.35" was used on most 60's A-833s, a 4.80" was used on hemi's 440s, and some 71-74 HD applications, and a 5.125" was used on 1975-1987 A-833-OD's.

Gear ratios varied from application to application. Besides the production ratios, additional ratios were available from Direct Connection in the Seventies. Below is a list of commonly found production ratios.

Year and Application	1st	2nd	3rd	4th
1964-1966 6cyl, V8 A-bodies, some 70s 318	3.09	1.92	1.40	1.00
64-70 B/C/E-bodies, 67-70 A-bodies, early 66 Hemi	2.66	1.91	1.39	1.00
66-70 hemi and some 440s	2.65	1.93	1.39	1.00
some 70 model	2.47	1.91	1.39	1.00
70 6bbl-340s, HP applications of B and E bodies incl. 340, 400, and 440s.	2.44	1.77	1.34	1.00
75-79 overdrive A and F bodies 75-87 overdrive trucks and vans.	3.09	1.67	1.00	0.73

 

Chrysler used Hurst shifters on all four speeds except for the Inland supplied shifters of the 1966-1967 years. Mopar Performance and Hurst can still supply most of what you'll need.

Bellhousings were briefly mentioned earlier while discussing input bearing retainers. Most A-833 bellhousings were cast iron until the seventies. The 1964-1966 slant six A-833 bellhousing is unique as it is the only Bellhousing that facilitates a four speed slant six unless an overdrive is used. In 1968, Chrysler began making one small block bellhousing for both the three speed and the four speed and, thus, carried both bolt patterns.

Four speeds were available in C-bodies from 1965 to 1969 (possibly 1964, though not confirmed). The 1965 C-body unit is identical to the 1964-1965 B-body unit except the mount provision on the tailshaft housing is different and accepts a C-body isolator mount, which is wider. The 1964-65 B-body unit used the same isolator that all B-bodies used from 1966-1970, and all 63-66 A-bodies. Here is a picture of the 1965 C-body A-833 with the C-body mount.

The overdrive gear box inverts the 3-4 front lever so it points down. All other A-833s have both levers pointing up.

Notice the E and B bodies shifter mount boss positions.

Running Changes

Year	Platform	Change
1964	A	introduced for 273cid V8s and 225cid slant sixes with 3.09 first gear set.
1964	B/C	introduced for big block applications.
1966	A	discontinued for slant six applications.
1966	A/B/C	Slip yoke output shaft adopted.
1966	A/B/C	speedo cable form factor change.
1966	A/B/C	Hurst shifters replaced by cheaper Inland shifters.
1966	B/C	30 spline output shaft adopted for all B/C-body A-833s (same as 727)
1966	A	26 spline output shaft adopted for all A-body A-833s (same as 904).
1967	A	30 spline output shaft adopted for 383cid A-body applications.
1966	A/B/C	Inland shifters replaced by superior Hurst shifters.
1968	A	30 spline output shaft adopted for all A-body A-833s.
1968	A/B/C	VIN plate provision added to pass. side of main case.
1968	A	307 rear bearing adopted.
1968	B/C	larger 4.80 in. IBR used with 23 spline 383 applications.
1969	C	C-body A-833 application discontinued.
1970	A/B/E	synchronizer ring stype change.
1970	A/B/E	detent ball interlock replaced by lever design.
1970	B/E	308 rear bearing adopted.
1970	B/E	rear mount position moved forward to allow for a single B/E crossmember.
1971	B	introduced for 340cid B-body applications.
1971	B/E	18 spline units installed in 383 applications.
1973	B/E	18 spline input discontinued.
1975	A/B	non OD A-833s discontinued.
1975	A	OD A-833 introduced for A-bodies, later available in D-100s and F-bodies.

VIN location and casting numbers

To comply with new Federal requirements, VIN numbers were stamped into engines and transmission begining in 1968. For A-833's, only a portion of the VIN was stamped on to the pad. The pictures below show the location of the pad. the PP833 2441 indicates the plant (PP), the model '833', and the rest is the assembly date. In the example, the VIN portion is 8B340272. The first 5 characters are missing (for example "BH23B). Of what remains, the first "8" means 1968, and "B" means the car was from the Hamtramck, MI plant. Also, some were stamped only with the last 7 characters of the VIN, beginning with the plant code.

here is a picture of the VIN pad, VIN pad + casting no., and the pass. side of the A-833

additional notes:

Overdrives came with both cast iron and aluminum cases (a cast iron A-833 weights about 150 pounds!). The most common OD units come in the F-body/A-body length, however a trunk length unit was also produced.

In the seventies, long tailshaft A-833s came with both the E-body shift mount boss (at the rear of the tailshaft) and the B-body shift mount boss (ahead of the rear trans mount). Sixties's B-body and C-body A-833s came with only the forward set of mounting bosses.

For many year mopars, crossmembers varied from automatics to four speeds.

For more information on the A-833 four speed, see the SlantSix.org article on the subject. Also see: "Gear Grabbing" Mopar Muscle Magazine, March 2004.