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BY RICHARD EHRENBERG. Copyright © 1989 Richard Ehrenberg. Reprinted by permission.First printed in Mopar Action
Any transmission can expire, but Chrysler’s A-833 4-speed is much less likely to do so than others. When surgery is required, however, it is helpful to know the patient, its problems, and which internal organs can be transplanted.
To ensure the continued well-being of your Chrysler 4-speed, let’s take a guided tour of the various versions produced, from the grandfather of performance Mopar gearboxes in 1964 up to today’s aluminum youngsters.
It’s the spring of 1962. Dodge’s 413 Ramcharger and Plymouth’s Super Stock are cleaning house at the nation’s drag strips. The new but already legendary A-727 Torqueflite automatic transmission has made Chrysler the undisputed ruler of the S/SA class. In S/S, though, things aren't so rosy. The hard-shifting, ratio-short manual is proving to be somewhat less than the hot ticket for trophy gold. Something needs to be done, and fast.
Back in Highland Park, the drivetrain folks are burning the midnight oil. They try the Warner Gear T-10 used by the Brand “C” and “F” boys, but it just can't handle the Max Wedge’s MoPower. The die is cast and plans are made for a new gearbox that will be able to take the abuse of anything the engine boys can dish out. Unfortunately, designing an all-new gearbox takes something that Chrysler is short on: time.
For 1963, Chrysler has to sell some cars with the T-10, mostly to counteract the street charisma of the 4-speed 406 and 409 cars. Still, Chrysler knows better than to sell 413s with the T-10, as this would result in blown-up boxes from coast to coast.
New model intro time, fall of 1963: At last! An all-new transmission, designated the A-833, is available in everything from 6-cylinder Valiants to rip-snortin’ Max Wedges. Equipped with a standard Hurst-Campbell “Competition-Plus” shifter and four fully synchronized forward speeds, it is built in Chrysler’s Syracuse (New York) New Process Gear plant. Even in 1989, it was the largest, strongest, and heaviest four-gear passenger car transmission ever built in America.
From day one, there were two distinct versions of this box: A-body (later to be used in F-bodies) and B-body (also to be found in later C- and E-bodies). Initially there were three main version-to-version differences: extension housing and mains haft length, low-gear ratio and rear-flange size. The A-car box, while every bit as strong as its larger cousin, carries a 3.09-to-1 low gear, to launch small cars with even smaller mills.
For 1965 there was only one noteworthy upgrade: the 1-2 shifter fork is redesigned to ease second-gear powershifts.
In 1966, though, several important changes appeared. First (and worst), the Hurst shifter was eliminated, replaced by a hollow-shaft Inland unit. Enthusiasts generally agree that this was a giant step backward, but Joe Average liked the reverse lockout feature. Second, the ball-and-trunnion front U-joint flange was gone, replaced by a more typical sliding-spline yoke arrangement.
A new speedometer pinion setup allowed more precise calibration (earlier ones were on a small cable-mounted adapter; starting in 1966 they use larger pinions and adapters). Also, except for the very early production cars, the 8-cylinder A-bodies came with the B-car’s 2.66 first-gear ratio.
Most importantly, another gearset was incorporated for the new Street Hemi models, featuring Oilite™ bushings lining each gear and new gear tooth angles for more strength. Hemi cars also had a new, larger main drive pinion (input shaft), with a larger (No. 308) bearing and retainer, and a new coarse-spline clutch disc. A unique, beefier clutch release bearing completed the package.
For 1967, a major flaw was corrected: The synchronizers and brass stop rings were redesigned to eliminate stop ring breakage on hard shifts. Luckily, these upgraded synchros can be retrofitted into the earlier transmissions. (This basic synchro design has survived right up through 1989!)
Then the 1968 models hit the streets. Gearjammers coast to coast were dismayed to find that the new Road Runner muscle car was stuck with the same lousy Inland shifter. Soon, though, Chrysler seemed to have had it “up to here” with the complaints, because shortly after the introduction, the Hurst shifter reappeared across the board, now dressed up with a new simulated-walnut shift knob.
The next noteworthy revisions came in 1970. First, a new 2.47-low close-ratio gearset was introduced for the T/A and AAR E-bodies (it later becomes standard in most 4-speed cars). Then the outrageous “pistol grip” shifter was released; this has become a much-sought-after restoration item. It consisted of a beefy, flat chrome stick with two woodgrain grips attached to each side and a shift-pattern logo cap on top. Cars equipped with this shifter also enjoyed a new set of transmission levers, punched with an extra set of holes for those who want extra-short-throw shifting.
The major change for 1971 (actually a late-’70 running change) is a redesign of the side cover and interlock mechanism. New sheet-steel interlock levers replace the old pin-and-balls type. The setup required new internal shift forks, which were now made of cast steel instead of brass. The entire side cover setups can be interchanged either way, which is useful, since the ’70-down type is generally regarded as better for drag racing and serious abuse.
Jeff Crane added: “I worked on some of those overdrive transmissions. The slant six would easily outlast the overdrive gear set. I rebuilt a few of them, changing the gears that wore out, to make them stop jumping out of 4th gear. Perhaps lubricants were not up to the task of lubing a gear set that drives continually for over 100,000 miles; or maybe the metallurgy was not up to the task.”
Another event for 1971: Chrysler’s Performance Parts Services released aluminum cases and extensions to the general public. A few had been made for the ’65 drag Hemis, but they were, for all practical purposes, nonexistent.
Also for ’71, 440 and Hemi cars with the coarse-pitch gears receive a new gearset with a 2.44 low. This applies only to cars with these engines, and they continue to feature the bushed mains haft gears and coarsespline clutch input.
Through the early ’70s, Chrysler sort of coasted with the A-833, no major revisions being introduced. Is that bad? Not really. Can you improve upon perfection?
Chrysler responded to fuel crises with the 1976 Dart Lite and Feather Duster. Lightened with several aluminum panels and other “dietized” components, the major new mechanical piece was a revised A-833 with drastically different gear ratios. [Editor’s note: this was launched during the 1975 model year, according to contemporary documents.]
The 3.09 first gear of the former 6-cylinder cars remained intact, but third gear was changed from 1.40- to 0.73-to-1. That’s right, third is overdrive and fourth is direct. A simple flip of the gear lever on the side cover gives the driver the illusion of three normal speeds and a fourth that is overdrive.
Editor’s note: Chrysler described the change as “an A-833 four-speed transmission, converted over to a three speed manual transmission with an overdrive gear ratio.” It was used with both the 318 V8 and 225 slant six. After the 1975 run, Chrysler switched to a finer-pitched gear tooth design to reduce the noise of the 1975 models, and changed the overdrive from 0.73:1 to 0.71:1. It used a steel housing except on the Feather Duster and Dart Lite, where it had an aluminum case and extension housing.
This transmission switched to a new superlarge front bearing retainer, even larger than the old “Hemi” models. This eased servicing as the main drive pinion was now removable from the front. The case and extension were cast in aluminum; the redesigned box bushings pressed in rigidly to support the countershaft, but the overdrive unit had no such bushings. In fact, the countershaft holes were reamed oversize, allowing the countershaft to “float” (supposedly for “gear rattle suppression”). It then required a shorter countershaft and cupped plug at the front to prevent oil leakage.
Many swaps are feasible within the Chrysler manual transmission family.
First, all 1970-and-up 8-cylinder clutch housings are drilled for both 3- speed and 4-speed bolt patterns. Except for the ’65-down cars, nearly all models used the large output-shaft spline, the exception being some late 1970s Slant Six A and F bodies. There were only two rear motor mount locations, and crossmembers were available to accommodate each. The bellhousings generally contained enough “meat” to allow remachining for either the Feather Duster or Hemi-size bearing retainer.
When buying a used box, make sure it has the shifter mounting bosses where you need ’em for your vehicle. Select a transmission that will mate with the clutch disc you'll be using, and be sure to have the correct release (throw-out) bearing to fit your box’s front bearing retainer. The mainshaft rear spline (output shaft) must also mate with your prop shaft, but, as we've said, that is generally not a problem area.
The accompanying photos should help guide you through some of the more common swaps, differences, repairs and upgrades and clue you in as to what to look for at the local boneyards and swap meets. We've pretty much ignored the one-off race pieces, such as the slickshift synchroless conversion and the full race “red-stripe” gearsets, to concentrate on the more readily available, mass-produced parts.
If you’re tired of being shiftless and winning automatically, get out the tools and bolt in another gear!
See more articles by Rick Ehrenberg at allpar • at Mopar Action
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Mopar (Chrysler, Plymouth, Dodge, etc) four speed manual transmissions.