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CHAPTER 1

HISTORY OF THE A-833

The years 1962 and 1963 marked the beginning of serious horsepower packed into a plain package at Chrysler Corporation. With the advent of the 413 and 426 Max Wedge and later, the 426 Hemi, Chrysler found itself behind the eight ball when it came to manual transmissions. Particularly when it came to 4-speed transmissions. Chrysler typically used the BorgWarner T-85 3-speed transmission. However, most of its dragstrip competitors had manual transmissions with four forward speeds. This put Chrysler at a disadvantage.

At the time, the current offering in a 4-speed was the BorgWarner T-10 transmission. This unit proved to be a disaster, as it could not take the horsepower that the 413 and 426 Max Wedge engines were creating. With the new 426-ci Hemi on the horizon, Chrysler engineers knew that they needed to create a stronger 4-speed transmission. The engineers at New Process, part of the driveline division of the Chrysler Corporation in Syracuse, New York, put their heads together. In 1964, they released the A-833 4-speed manual transmission.

This transmission was created out of necessity due to the weakness of the BorgWarner T-10, and it filled the void perfectly. It was arguably the strongest passenger car manual transmission ever made. This strength is due, in large part, to the 3.5 inch center distance between the input shaft and the cluster gear. It was initially designed with a 23-spline input shaft, as well as a cast-iron main case, tailhousing, and sidecover.

The A-833 4-speed transmission went through many design changes and enhancements throughout its production run from 1964 until 1986. Without a doubt, the A-833 is the most varied design transmission during the muscle car era. Just one example of this is the entirely different front bearing retainers that were used. But there were many other changes as well.

One of the many design changes of the A-833 was the front bearing retainers used. Six common bearing retainers that are used on the A-833 transmission (shown here) were made of cast iron and used a seal that was pressed into the retainer itself. The retainer used a paper gasket to seal against the case. The four bolts used to fasten the retainer must have sealing compound applied to their threads, as the holes extend into the interior of the main case. The only one not pictured is a 1975-only that used a small 307 bearing and had the large 5.125 inch OD.

A-833 Design and Component Changes

The A-833 went through a few platform changes throughout the years. Along with these external changes, there were a myriad of internal ones. They will be explored in the following pages.

1964–1965

The initial A-833 configuration had a 23-spline input shaft and a splined output shaft with a threaded section at the end. The flange slid onto the splines and was retained by a special serrated locking nut and washer. A flange connected to a driveshaft equipped with a booted universal joint, called a “ball and trunnion,” via four 3/8 -24 studs and a special tall corresponding nut. No washer was used. The A-Body flange was smaller than the B- and C-Body versions.

All three 1964–1965 tailhousings are displayed here. The top is for an A-Body, the middle is for a C-Body, and the bottom is for a B-Body. Notice the speedometer gear keeper bolt location at four o’clock on the B-Body versus one o’clock on the C-Body. The transmission mount flange is also wider on the bottom of the housing on the C-Body.

There were two versions of this configuration. The A-Body had a tailhousing length of 10½ inches less the flange. The B-Body and C-Body version had a length of 16¼ inches less the flange.

There were also different first-gear ratios for each of these configurations. The A-Body had a 3.09, and the B- and C-Bodies had 2.66. The 1964 and some 1965 production units used an oil slinger between the input shaft drive teeth and the front bearing. The initial shift fork design (in 1964) was a very small paddle-type 1-2 made of a brass alloy and a steel 3-4 fork.

These forks were used in 1964. The top fork is the small paddle-type 1-2 fork that caused problems with power shifting because of unequal pressure on the slider. The lower 3-4 fork was steel and worked well.

This shift fork design proved to be an issue for power shifting, as it did not spread the force out over the circumference of the slider, loading one side of it. The fork was redesigned for 1965, and this fixed the problem. The 3-4 fork was also switched from steel to a brass alloy that year. The 18-spline input shaft also was introduced in late 1965.

The 23-spline front bearing retainer had a casting number of C-94796. This was the only retainer used on 23-spline units until 1967. The B- and C-Body units used a 307 bearing in the front and mid location. A 206 bearing supported the rear of the output shaft very solidly. This design was favored for competition in NASCAR, even after the slip yoke output shaft replaced it in normal production.

As you can see, the improved 1-2 fork design for 1965 (top) has a wider span to equalize pressure to move the slider more evenly. The 3-4 fork (bottom) was changed to a brass alloy material that was consistent with the 1-2 fork. This was likely done in order to streamline manufacturing so that two different materials were not needed.

1966–1967

There were several changes for 1966. One was the elimination of the slinger on the input shaft. Another change was that the sidecover bores were a heavier casting with improved gusseting. These were initially a very thin casting in 1964 and 1965 and were prone to cracking. The input and main bearings stayed the same (307) size as the previous years.

The largest change was the output shaft design. It went to the much more common “slip yoke” type. This change occurred on the 727 Torque-Flite automatic transmissions in 1965. The slip yoke had splines at the rear end of the output shaft. This allowed a yoke attached to the driveshaft via a universal joint to slide on the shaft depending on driving conditions and suspension travel.

This photo shows the eight different A-833 shaft configurations throughout the entire production run. Unlike other auto manufacturers, the A-833 had many different configurations. The shafts from top to bottom are: 1. 1964–1965 B- and C-Body 1:1 final drive ball and trunnion type, 2. 1964–1965 A-Body 1:1 final drive ball and trunnion type, 3. 1966–1974 B- and E-Body 1:1 final drive 30-spline output, 4. 1966–mid-1967 A-Body 1:1 final drive 26-spline slip yoke type, 5. mid-1967–1975 A-Body 1:1 final drive 30-spline output, 6. 1975–1986 truck overdrive 30-spline output, 7. 1977 F-Body overdrive 26-spline slip yoke output, and 8. A- and F-Body overdrive 30-spline slip yoke type.

This design did not allow for a support bearing as the previous trunnion design had. A bushing was now installed in the tailhousing. This slip yoke–type output shaft was available in two different configurations, a 26-spline design for the 1966 and early 1967 A-Body and a 30-spline for the later A-, B-, and C-Body cars.

In 1966, the 3.09 first-gear ratio was discontinued. This would be shelved until the mid 1970s. It was the first year of regular production of the 18-spline A-833 as well. This was standard equipment in vehicles equipped with the 440 and 426 Hemi engines. This is how the 18-spline A-833 became known as a “hemi 4-speed.” The 426 Wedge (Street Wedge for 1964–1965 and Max Wedge for 1964) were not equipped with the 18-spline A-833.

The early speedometer “gear on cable” design was also ditched for 1966. In this new design, the cable and driven speedometer gear were independent of each other. This change allowed much more precise speedometer calibration as well as the ability to produce and supply fewer parts by sharing the design with the automatic.

1968–1969

The first major redesign regarding internals of the A-833 occurred in 1968. At this time, the synchronizer assemblies were redesigned. The neutral detent in the slider was much wider and deeper than before. In addition, the strut keys were redesigned to match the slider detent. They were shortened from 1.175 inches long to .950 inch long. The keys stayed the same width at .216 inch wide. The change in strut key design required a synchronizer hub design change as well. The slots where the keys ride needed to be machined deeper to compensate for the taller strut key. Even with the changes, the brass synchronizer stop rings stayed the same.

Another significant change was the bearing size increase on the 18-spline A-833. This was increased to a 308 series bearing. New Process used MRC as the OEM bearing supplier throughout the run of this transmission. The upgrade to the 308 series bearing was a simple design change. The standard 308 bearing had a larger internal bore than the 307 bearing, and it was actually slightly thinner at .795 inch thick. The 307 that was being used in the A-833 was .825 inch thick. The issue was that everything was already designed for a specific bore diameter and bearing thickness. Therefore, the 308 bearing instantly became an application-specific bearing design. This spelled availability troubles several years ago when SKF Corporation bought the MRC Corporation. Ultimately, the 308 was dropped from production. Several aftermarket offshore vendors picked up production. However, there have been quality issues with some of these regarding size tolerances.

This shows the 307 bearing (top left), 308 bearing (bottom left), 206 bearing (top right), and output shaft bushing (bottom right).

Bearing retainers also changed in 1968. Until that year, all bellhousings had a register hole of 4.354 inches. Beginning in 1968, all big-block bellhousings received a register diameter increase to 4.805 inches. This required casting of a new bearing retainer. The new bearing retainer still had a 3.70-inch bolt circle, but it now had an outside diameter of 4.807 inches. This new bearing retainer was used in 1968 and 1969 on big-block 23-spline A-833 units because they still had the 307 bearing.

The 18-spline version got a new retainer as well due to the new 308 bearing. The bolt circle was increased to 4.16 inches.

The last noteworthy change for 1968 was the introduction of the vehicle identification number (VIN) to the transmission case. This information was stamped on pads and began showing up as a rough casting on the passenger’s side of the main case toward the front about one-third up from the bottom in mid-1967. However, they were not machined flat or stamped until 1968. There were two different size pads. The early one was 7/8 inch tall and about 2¼ inches long. Beginning in 1969, the pad length was increased to 3 inches long.

Take note that only transmission assembly information is present. This is the lower row of letters and numbers on a warranty replacement transmission. The meaning of these characters will be explained in Chapter 3. The upper row that would include vehicle assembly information is absent.

This case shows the initial casting for the VIN pad inclusion. This case was cast in December 1967. Note that it is just a rough casting and that it is shorter than the later cases.

These cases are both 1968 production cases. As you will notice, the font is very different on them. This suggests that all assembly plants did not use the same font. The first photo shows a 1968 4-speed that was removed from a vehicle built at the St. Louis, Missouri, assembly plant. The second picture shows a 1968 4-speed that was from a vehicle built at the Hamtramck, Michigan, assembly plant.

There were actually a few variations to the information stamped into this pad. New Process stamped all pads with the assembly information of the transmission including the model number, assembly date, and quality built that day. The vehicle-specific information was stamped at the vehicle assembly plant. In 1968, these numbers were hand stamped using individual stamps. This is evident because characters were not in a straight line. Stampings from 1968 also stand out because characters used were typical off-the-shelf fonts that were readily available. These two things changed in 1969; character sets were used to keep things lined up and a special font was also used. The new font was tall, narrow, and had some oddly shaped letters and numbers. It is my opinion that this font was developed to prevent vehicle fraud.

Prior to 1968, as long as the casting dates of the individual components predate the vehicle production date by the correct “window” of two weeks to two months, it can be argued that the transmission is the original piece. VIN numbers are explained more in Chapter 3.

1970

This was another year of some noteworthy changes to the A-833 transmission. The B- and E-Body transmission mount boss was moved forward on the tailhousing to be consistent with the location of the transmission mount flange on the TorqueFlite automatic transmission. A three-bolt shifter mount flange was also added at the extreme rear of the tailhousing for E-Body and later B-Body cars. This effectively made the dual shifter mount tailhousing fit both B- and E-Bodies. Prior to this 1970 change, an automatic crossmember and a 4-speed crossmember were in B-Bodies. The transmission mount was the same between the two.

This transmission case is from a 1970 vehicle. Note the evenly spaced and straight VIN stamped on the case. By this time (actually 1969), character sets were being used to make numbers easily readable. You will notice a different font than was used on either of the earlier VIN pads. This became the standard font used on all A-833 4-speeds built from 1969 forward.

This is a service replacement transmission. It has only the transmission assembly information on it with no larger VIN. It is obvious that it has not been tampered with.

The Plymouth A.A.R. `Cuda and the Dodge Challenger T/A were the first vehicles to receive the new 2.47:1 gearset.

In addition to gear ratio change, the A-833 also received a synchronizer design update. One of the recurring issues with the previous two synchronizer designs (that used the exact same brass synchronizer stop rings) was cracks forming at the sharp corners of the slots in the rings. These slots were used to prevent the synchronizer ring from spinning by using a strut key that fit into the slot and kept it stationary. The new design used a tapered slot and included a brass lug around the outer circumference of the ring. This required a shorter strut key. Therefore, the key was shortened from .950 inch to .778 inch and increased in width from .216 inch to .382 inch.

All A-833 transmissions behind big-block engines received 308 front and rear bearings beginning in 1970. This required a new bearing retainer yet again. It shared all dimensions of the 1968 and newer 18-spline bearing retainer except the tube diameter, which was the same as the standard 23-spline.

1971–1974

This marked the first full year of production for the 2.47 (23-spline) and 2.44 (18-spline) gear ratios, interlocking lever sidecover, and lug-style synchronizers. Beginning with these gears, efforts were made to reduce costs. The gears were now single carburize–hardened instead of double carburize–hardened. In 1971, the “ball and detent” interlock mechanism was changed to the “double interlocking lever.”

The ball and detent design used a tube with a pair of spring-loaded balls with a dowel in between them. The shift forks are not part of this interlock mechanism. The interlocking lever design used two flat steel plates stacked and spring loaded, and the shift forks are part of this mechanism. Therefore, brass alloy was not up to the task, and forged steel forks were used to stand up to the repeated surface abuse of the levers. The idea behind both interlock types is so that the transmission cannot be put into two different forward gears at the same time. These interlock styles are the subject of some debate among enthusiasts. The double interlocking lever–type had better steel shift forks. However, it can be argued that the ball and detent type allowed easier and smoother shifting.

This shows the difference between the early and late sidecover interlock design. Top is later interlocking lever design; bottom is the earlier ball and detent design. It is generally accepted that the earlier type was better for racing. However, the later type used a more durable steel shift fork. Very often, people cut the pin off the later steel fork and use it in the earlier cover.

Note the additional pin on the stem of the 1-2 fork (top). This extends out farther than the earlier shift fork and becomes part of the interlock mechanism. This is, in part, why the material changed from brass to steel. The 3-4 fork is below the 1-2.

The last full year of production for the 18-spline transmission was 1971. With decreasing power outputs and the elimination of the 426 Hemi from the engine lineup, this heavy-duty unit was no longer needed. It continued to be installed in 440 and 440 six-pack cars into 1972; then it was phased out.

One final 1971 change was a provision for a switch for the 1971 sidecover that was activated when the transmission was put into fourth gear. This retarded the timing for decreased emissions. I am not aware of exactly which vehicles received this switch. Many of the interlocking lever–type sidecovers had this provision drilled and tapped with a plug instead of a switch.

The A-833 went on until 1974 largely unchanged in B- and E-Body cars. The long tailhousing configuration with a 1:1 final drive ratio ended in 1974 with the official end of the E-Body vehicle platform.

1975

The transition into the overdrive version of the A-833 began in 1975. This year was the end of the 1:1 final drive A-Body unit. This limited-production 1975 1:1 transmission was unique, as it still retained the small 307 front bearing. But it had a bearing retainer that was 5.125 inches in diameter to mate with the bellhousing for the overdrive version of the A-833. The bearing retainers eliminated the need for an adapter ring to use an overdrive bellhousing. However, they were very scarce. This was the only year (apart from 1964–1965) that the steep 3.09 first gear was used with a 1:1 final drive.

1976–1986

From 1976 until 1986, only the overdrive version of the A-833 was available. There were several changes during the last decade of production. There were two gearsets and output shaft designs in the F-body transmission. The F-Body version began with a cast-iron main case, tailhousing, and sidecover and a 30-spline output shaft. In 1977, an aluminum main case and tailhousing was used on the F-body cars, but it retained a cast-iron sidecover. The output shaft on some units was reduced to 26-spline, similar to the 1966–1967 A-Body 1:1 mainshaft.

The year 1986 heralded the end of the A-833 in passenger cars. The truck version began with a cast-iron main case, sidecover, and tailhousing. It evolved into an aluminum main case and sidecover with a cast-iron tailhousing. There were two different aluminum truck sidecovers. Their functions were identical, the casting just varied slightly.

In 1982, the synchronizer assembly was redesigned for the A-833. This redesigned assembly shares only strut keys and strut key springs with the mid-1970 version. The slider and hub are different and used the lug-style synchronizer rings. The sliders began a torque lock design that was similar to the design used in other 4-speed transmission models throughout the years.

In addition, the 1-2 shift fork design changed during this time. The 1-2 fork was enlarged to extend deeper into the slot in the 1-2 slider.

The difference between the early 1-2 interlocking lever shift fork and the late design is shown here. The early design fork (top) stamped F99385 was redesigned for the release of the overdrive version of the A-833 transmission. The design change is obvious, as there is more “meat” on the later design fork (bottom) stamped F-13636.

A-833 GEAR RATIOS

The A-833 has had a number of different gear ratios throughout its 23-year production run.

I would like to point out some notes regarding the gearsets mentioned below. First, all 18-spline speed gears have a dimpled oilite material bushing inside the bore of the gear. This is present in the first, second, and third gears. On 23-spline transmissions, the internal gear bores are not bushed. Both designs rarely have problems unless lube levels are allowed to drop too far.

In addition, a set of reverse idler teeth is present on all cluster gears. These always number 17. These are the same on all Chrysler A-833 cluster gears, whether in regular production or race gearsets. There is, however, a different reverse idler gear in some overdrive transmissions. These are identified by either one or two hashes marked on the cluster gear on the first gear area.

If you are observant, you will notice that most of the specialty race sets use the 23-spline input shaft. The way I understand it, in order to adhere to the “factory equipment regulations” the 23-spline input must be used instead of the 18-spline. It is for this reason that Chrysler actually made input shafts that were 23–clutch splines, but had a 21-tooth gear on the inside of the transmission case that was the same as an assembly line 18-spline transmission. These gears were all 9310 material. They were identified by S K numbers. To date, I have not found out the actual reasoning for these S K numbers; however, the number is present on these gears.

The red-stripe drag gears had unfinished synchronizer cones and every other synchronizer tooth was missing. This brought the number down from 36 to 18 teeth. The synchronizer slider was modified to remove every other internal spline to match the gears. This also brought the number down from 36 to 18 splines. These were meant for use in an unsynchronized racing situation. The gears typically had a short life, but were plentiful, so they were simply replaced. Chrysler made the white-stripe gears like this as well. These gears are identical to the assembly line white-stripe gears except for the synchronizer tooth arrangement, which was the same as the red-stripe drag gears. These gears are commonly referred to as “slick shift” gears. This was the preferred setup for drag racing versus a stock synchronizer setup. A solid inner hub was used with this arrangement even though a stock slotted hub could be used by removing the strut keys and synchronizer springs.

NOTES:

1: The cluster gear is identified by one thin hash mark machined in the barrel area. Speed gears have a thin hash mark machined on the outer edge of the gear teeth on the second and third gears. The input shaft has a slightly wider hash machined at the base of the pilot tip. This will interchange with the 1977 and Up OD input shaft.

2: The cluster gear is identified by two hash marks machined in the barrel area. The first, second, and third gears are oilite bushed and have no hash marks.

3: The cluster gear is identified by three hash marks machined in the barrel area. The outer edges of the second and third gears have three hashes machined in them.

4: The cluster gear is identified by six hash marks that are machined in the barrel area. The first, second, and third gears are oilite bushed. The second and third gears have two hash marks machined into the outer edges of the teeth. Be careful not to mix these up. The two-hash-mark speed gears do not match the two-hash-mark cluster gear.

5: All speed gears have a wide hash mark machined in the outer edge of the teeth. The cluster gear also has a single wide hash mark machined in the barrel area. This is known as the “high helix” OD ratio.

6: All speed gears have a single wide hash mark machined into the outer edge of the speed gears. The cluster gear has a wide hash mark machined into the barrel area of the cluster. This gear is recognizable when compared to the 1964–1965 A-Body because of the much larger third gear row of teeth.

7: First gear interchanges.

8: First gear interchanges.

Once things started to evolve, aftermarket companies modified factory gears and made replacement gears for the A-833. Liberty’s Gears in Michigan designed a synchronizer setup known as “Pro shift.” This setup actually removed all of the factory synchronizer teeth and replaced them with a hardened ring that was welded to the gear. This ring had 12 larger lugs on it. You could use a factory slider that was modified by removing two splines and then leaving one. This system was a significant upgrade to the slick shift setup for two reasons. It shifted better and the gears could be rebuilt. When the lugs were damaged, the ring was cut off and a new one was welded on. Liberty’s also made additional first-gear ratios for the 18-spline transmission, including a 2.93:1 first gear ratio. These gears were not made in the stock configuration.

You will notice, if you look closely, the difference between some of the clutch splines and also the identification markings on the drive teeth in these seven stock factory gear ratio input shafts.

Doug Nash had a similar arrangement as the Pro shift. These pieces could be interchanged. Another company named G.E.R. also made gears for the A-833. They had a similar setup, except that it had 10 lugs instead of 12. It also required the use of G.E.R. hubs, whereas Liberty’s and Doug Nash used a stock configuration hub. ■

Again, close inspection reveals identification grooves that are machined in the barrel area of the gear. This allowed quick identification between the seven different assembly line ration cluster gears.