By on April 7, 2022

The recent Rare Rides Icons post on the 1990 Chrysler Imperial Super-K Gingerbread Cookie Edition generated a few comments not only about the subject in question but its four-speed UltraDrive transmission. It seems more than one of you wants a discussion – no – an essay on the UltraDrive. Wish granted! Here we go.

Chrysler had a long history with its TorqueFlite line of transmissions, applied to rear- and front-drive vehicles. The transmissions were many, varied, and of manual and automatic persuasion. TorqueFlite had its origins in 1956, and though the name went away circa 2000 it has since been revived. But the various TorqueFlite transmissions, though reliable and long-lived, were a bit basic in their format. The automatic only had three speeds.

Thus in the mid-Eighties, Chrysler decided to develop a line of transmissions separate from the TorqueFlite that they’d eventually call UltraDrive. The new transmissions were designed exclusively for front-drive, transverse engine applications. The front-drive and transverse setup was all the rage at the time (still is), and after the debut of the K platform cars in 1981 seemed the way forward. The UltraDrive was to be advanced, modern and was deemed the successor to the TorqueFlite at least in front-drive applications.

The modernity of the UltraDrive’s design was largely due to its electronic operation. It was one of the first automatic transmissions commanded by computers. Inside, there was an ECU (electronic control unit) that determined shift points via learned behavior based on how the car was driven. The computer inside the transmission activated solenoids to control the hydraulics. Said solenoids replaced the many valves and servos that were part of the normal operation of an automatic transmission.

Though the electronic transmission was an advanced idea at the time, Chrysler had experimented with such a unit in the Seventies. Years later with financial savior Lee Iacocca at the helm, Chrysler decided to pursue that transmission and additional “electronic marvels,” which lead to the employment of former NASA engineers. Their creations included the issue-prone fuel injection and flaky electronic dashboard of the early Eighties Imperial.

The Seventies test mule was a Plymouth Volare with a trunk full of computers. It was this automatic Volare that formed the basis for the four-speed UltraDrive. Chrysler bet big on its new transmission, and one person in the board room, Iacocca, felt the technology was ready for its debut. It wasn’t, but we’ll get to that in a moment.

And so it was in 1989 that Chrysler implemented the new A604 into almost every front-drive vehicle it made. From basic cars like the Dodge Shadow and Dynasty to sporty cars like the Daytona, mid-market cars like the Lebaron, and even the company’s top front-drive offering the Chrysler New Yorker. A few front-drive cars were exempt from the A604, like the imported Colts, the Omni, and the Aries that saw its last year in 1989. It was a huge launch for an all-new transmission.

Other than the new transmission, 1989 was a bit of a lackluster product year for Chrysler. Old models like Aries and Diplomat were on their way out, while the new Nineties product hadn’t arrived yet. The head of marketing at Chrysler knew there wasn’t much flashy happening, so he gave the A604 a fancy name, UltraDrive. Then he put it at the forefront of the company’s marketing materials.

The inherent problems with the transmission were almost immediately apparent. Given its rushed production, it’s generally believed the UltraDrive needed about another year in development. The A604s in new Chrysler vehicles often failed after a short period of time, but there was more to it than simple underdevelopment and mechanical unreliability.

It seemed there was also some lackluster planning during development with regard to transmission fluid usage. In all owner’s manuals of A604-equipped vehicles, there was a recommended fluid called Type 7176, or ATF+3. And while that fluid was specifically for Chrysler vehicles, there was another recommendation in the manual: Dexron fluid would work as a substitute if the ATF+3 was not available. This information was duplicated on the transmission dipstick as well.

Unfortunately, the transmission was designed only to work with the ATF+3 fluid. When owners took their cars into a shop to have the transmission fluid changed, Dexron was used much of the time. Dexron caused the transmission to fail, much to everyone’s surprise. The issue didn’t ruin the A604 and was often resolved with a drain and replacement with the correct ATF+3 fluid.

Chrysler learned that Dexron was not suitable shortly before the A604’s debut, as it put over a million test miles on its new transmission. For whatever reason, time or money, they didn’t change the labeling in the manuals, on the dipstick, or tell their dealers. A decade later, there were still shops that mistakenly put Dexron in the A604.

But that wasn’t the only common problem, as a built-in electronic “feature” caused much consumer chagrin: Limp home mode. The sensors in the transmission detected when there was a problem somewhere in the unit, and would default to limp home mode. Something as simple as a temporarily incorrect reading by a sensor caused the mode to trip. Once it did the error code was stored in the ECU, and the A604 entered limp home mode. That meant when put in drive, the transmission used only second gear.

The design was intended to allow consumers to take their car to a service center and prevent further transmission damage, or being stranded on the side of the road. But this feature was not clearly communicated to owners or dealers. When an UltraDrive was brought in to a service center in limp home mode, the problem was often diagnosed as a failure and remedied with a costly transmission replacement under warranty.

There was no backup plan for the transmission’s programming for limp home mode, only second gear. In the event a fault was detected in second gear, the transmission stopped operation entirely and the car wouldn’t move.

A604 had a simple learning logic built into its computer, in order to adjust shift points and harshness to how a driver behaved. It took a few days to work out what a driver wanted. This was not generally an issue if one person drove their Chrysler every day, forever. However, if two drivers shared a vehicle (like say with most family minivans) or if a car saw many drivers in a fleet situation, the transmission could never settle into a pattern. Thus when a driver got into an A604 vehicle for the first time, the transmission’s learned behavior was often disconcerting.

Widespread failures were publicized quickly, and as owner complaints piled up Consumer Reports took action: They removed the Caravan and company from their recommended list. This apparently sent Iacocca off the edge. Management was called to the board room in Highland Park and presented Lee with various data related to the UltraDrive’s failures.

Lee had a simple response and said “Look, I’ve got to go. I’ve got to take a leak. When I get back, I want one person in charge of this mess.” The job of fixing and re-engineering the UltraDrive was handed to one engineer, Chris Theodore. With his team, the A604 was torn down and rebuilt. Engineering issues were compounded by poorly made internal components, and then the units were slapped together poorly.

Chrysler addressed the problem with a quick redesign of the A604, finishing the engineering that should’ve been done before it went into production. The revised A604 was quickly rebranded as the 41TE. It included different solenoids, new valves, revised sensors, and numerous other changes to make it more reliable. Crucially, the 41TE had an ECU that was programmable.

There was great pressure from consumer groups for Chrysler to address its transmission problems, as Consumer Reports and the US.. Center for Auto Safety demanded action. Iacocca authorized a campaign to contact all owners with UltraDrive transmissions, to get them to bring in their problematic cars. The company also decided to waive the $100 deductible for warranty work, and extend the warranty coverage to service loaners. There was also a buyback option in the case where an UltraDrive car couldn’t be fixed.

Warranty claims died down quickly enough after the revised 41TE replaced the A604 version of the UltraDrive. While 1989 and early build 1990 cars were problematic, by 1991 the transmission reached acceptable levels of reliability. Around 500,000 cars were built with the initial and most problematic version of the A604.

After its trouble-prone and rushed birth, Chrysler got a lot of miles and many derivations out of the UltraDrive. It’s nearly guaranteed that you’ve come in contact with an UltraDrive-equipped vehicle at some point in life. More on that when we finish up in Part II.

[Images: Chrysler]

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54 Comments on “Abandoned History: The Chrysler UltraDrive Transmission (Part I)...”


  • avatar
    Mike Beranek

    Ah, these are the transmissions in Chryslers that go “tick tick tick tick” as the vehicle slows to a stop.

  • avatar
    FreedMike

    “It seemed there was also some lackluster planning during development with regard to transmission fluid usage.”

    What, they didn’t make the transmission run on Chanel #5, like a Turbine car?

    That’s some SERIOUS fail.

  • avatar
    Arthur Dailey

    I have to disagree with your comment that “by 1991 the transmission reached acceptable levels of reliability”. Our Grand Caravan ES which may have been among the most expensive vehicles you could purchase from a Chrysler dealer in 1992 was on its 3rd transmission when I passed it on with about 85k on it. And it had light duty, never towed and was never overloaded.

    The replacement a 1996 Caravan Sport ‘ate’ its first transmission at just over 45k.

    Meanwhile our 1993 ‘base’ Caravan with the old 3 speed transmission was still going with well over 300k when it was written off. We gifted it to my sister-in-law with just over 100k and the only maintenance it received was when I would take it to ‘instant lube’ shops to help her out or perform some quick driveway maintenance.

    Aston-Martin throughout the 1980s (and perhaps earlier) had ‘scouts’ in North America who purchased used Torqueflight transmissions which were shipped to Newport-Pagnell, rebuilt and installed in new Aston-Martins.

    • 0 avatar
      FreedMike

      I can see it now…two Veddy Veddy British Chaps wearing Harris Tweed sportcoats scouting the local junkyard for used transmissions from junked Dodges to ship back to Britannia to install in six-figure Aston Martins that will be sold to coked-up Master Of The Universe Wall Street types.

      Jolly good!

      (Sheesh, we wonder why British cars have the rep they do…)

      • 0 avatar

        And TorqueFlites were in things like the Monteverdi High Speed, and the Jensen Interceptor.

        • 0 avatar
          FreedMike

          Yeah, but I’m going to presume these guys were buying the transmissions NEW, versus hitting the pick-‘n-pull lot.

          • 0 avatar
            IanGTCS

            I remember an article years ago that mentioned they bought used ones. My understanding is they were pretty good transmissions and they were rebuilt so almost good as new.

          • 0 avatar
            Arthur Dailey

            According to ta ‘top executive’ for Aston-Martin who we met and spent some time with at their facility in 1989, since A-M took the transmissions apart and totally rebuilt them, they did purchase used ones. Usually out of old top end Chryslers. A-M at the time still ‘hand built’ each car at their N-P facility which looked like hangars left over from WWI.

            Found the following in different Aston-Martin forums.

            The Aston Martin Works Sale Newport Pagnell,9 May 2015,
            TWO A-727 OR TORQUEFLITE 8 AUTOMATIC TRANSMISSIONS
            As used in 1969-1986 Aston Martin Vantage and DBS V-8 and Lagonda models, used condition, each includes torque converter, both in working order when removed from vehicles converted to manual transmission.

            If you’re driving a newer automatic Aston, and you’re looking for the extra control provided by a manual gearbox, Rikki Cann will help. We carry out conversions from automatic to manual on some of the newer Aston Martin models, and all of the classic models. We can also upgrade the Torqueflight gearboxes that are fitted on classic V8 and Virage vehicles.

            I have a Aston Martin Virage Volante of 1994 with a 4-speed transmission A-727-A 4. Gearbox Number is PK5300 8148 1290 9917 Axle Ratio 3.54 (the AM 5.3 V8 engine has a range to 5.800 rev/minute). Aston Martin is not able to help me, they have a catastrophic documentation of the earlier years. I think it must be a conversion of the 727 or could it be a 518 Torqueflite?. Aston said, it’s a modified 727 four speed.

          • 0 avatar
            FreedMike

            @Arthur:

            Literally crazy that Aston Martin would charge upwards of a hundred grand in today’s money for a car with a USED transmissions. My guess is that little tidbit was kept as secret as the Coca-Cola formula.

        • 0 avatar
          bufguy

          Just as GM’s turbo hydramatic 400 was used in Rolls Royce

          • 0 avatar
            Mike Beranek

            Old Jaguars too.

          • 0 avatar
            Arthur Dailey

            @FreedMike: We were told this in the pub, after spending considerable time (and money) there. So he could have just been ‘winding us up’. And after 30 years memories of a bar conversation can be ‘hazy’. They were operating on a shoestring budget, and still hand built everything. So in theory taking a transmission apart, and rebuilding it by hand would result in superior performance to ‘dropping in’ one fresh of the assembly line. I suppose much like ‘blue printing’ an engine.

      • 0 avatar
        Yankee

        “Master of the Universe Wall Street types.” This is why I come here. What other automotive site are you likely to run into a reference to Tom Wolfe’s Bonfire of the Vanities?

    • 0 avatar
      sumgai1986

      Agree with you there. My 1996 Status chewed through 7, countem 7 ultra drive transmissions over it’s short life. All replaced under warranty.

    • 0 avatar
      DenverMike

      They’re the smoothest shifting transmissions ever, but there’s a price you pay. I demand a shift you can feel.

  • avatar
    sckid213

    My family had a duplicate of that 1990 T&C in the ad pictured above! It was pretty sweet for the time, maybe the equivalent of a Denali trim at the time?

    Went through trans #1 under warranty, #2 out of warranty, and #3 is what saw it out the door. All under 100k. I always remember my mom shifting into reverse and then after a delay slamming back. That was always the first warning sign.

    • 0 avatar
      sumgai1986

      I remember my neighbor growing up had the T&C while we had the Caravan. In retrospect, the only difference was bunched leather and vinyl wood decal, but it felt like a much nicer van.

    • 0 avatar
      sgeffe

      Even the venerable 3-speed TorqueFlite A-727s and 904s always clunked going into Reverse. Anybody know why?

      • 0 avatar
        texan01

        sgeffe it’s the slop in the rear axle and the driveshaft splines. My TH350 does the same thing but it’s a bit tighter on the slack.

        Dad’s 87 Dakota’s 998 (904 with lockup) did the same.

  • avatar
    ajla

    I’ve always thought that the tendency early minivans had to eat transmissions like they came out of a can of Pringles to be an underrated factor in people shifting to BOF SUVs in the late 90s. And it might still hurt the segment today.

    • 0 avatar
      Matt Foley

      That’s a pretty smart observation. The weak transmissions in the 2nd-gen Odyssey (and early 3rd-gen) might have sealed the deal. Imagine someone getting burned by a Chrysler minivan transmission failure in the 90s jumping to an Odyssey in the early 00s and getting burned again. “Screw this, I’m buying a Tahoe.”

      • 0 avatar
        eng_alvarado90

        And let’s not forget the Windstar. 2 out of 3 extended family members were burned by the AX4 transmission failing on them.

        • 0 avatar
          gasser

          I had the “pleasure” of owning a ‘95 Windstar, a brand new model. Despite the undersized brakes and poorly designed front suspension (which allowed limited alignment adjustment and therefore 7,500 mile brake pads and tires), the transmission lasted over 70,000 miles, running perfectly at trade in time. I had two friends with ‘95 Windstars who were NOT so lucky. My Windstar had replaced my ‘87 Mercury Sable station wagon which had 3 transmissions in 50,000 miles!!! Thank G-d for my purchase of Ford’s 6 year, 60,000 mile warranty!!!!

          • 0 avatar
            28-Cars-Later

            “My Windstar had replaced my ‘87 Mercury Sable station wagon which had 3 transmissions in 50,000 miles!!!”

            I realize the AXOD sucked but what were you doing to it?

    • 0 avatar

      Have to agree. The minivans taxed autos heavily. Lots of failures show up the larger the car. Honda had lots of auto failures too. In general 90’s FWD auto’s were pretty poor (the early 4 and 5 speeds) lots of failures. When I was in my teens and early 20’s having a friend say their car needed a new transmission at 100k miles was pretty normal. As an example when I met my wife she was driving a 91 Legacy that had the auto changes a month after she bought it right around 95k miles. Same with a friend with his 92 Plymouth sundance. Or my in laws with their 97 contour, across a variety of brands it was an issue.

      • 0 avatar
        ajla

        There’s irony that the 4T80 was quite stout for a transmission with a sideways engine while the Northstar it was paired with was such an expensive headache.

  • avatar
    SoCalMikester

    so it was fluid the whole time?

    • 0 avatar
      indi500fan

      No because they had plenty of failures with the factory installed fluid which was the correct stuff. This transmission was a very ambitious design, a technical leap forward both mechanically and electronically, that simply was released to production before it was thoroughly developed. Another year or 18 months would have done it.

      I know from personal experience at GM that there was a long period of stability with transmission designs in the 60s and 70s. A lot of expertise retired or was forgotten. And when it was time to do some advanced things like adding more speeds, new gear and clutch layouts, and electronics, the programs were planned with over-optimistic schedules.

      • 0 avatar

        “A lot of expertise retired or was forgotten. And when it was time to do some advanced things like adding more speeds, new gear and clutch layouts, and electronics, the programs were planned with over-optimistic schedules.”

        Reminds me Silicon Valley culture if you replace “retired” with “laid off”. Why laid off? Because of India. I hope in Austin it will turn out differently. But SW and FW is easily to update or patch.

        • 0 avatar
          golden2husky

          ….Reminds me Silicon Valley culture if you replace “retired” with “laid off”. Why laid off? Because of greedy fat cats that can’t get enough money for themselves…

          Fixed it for you.

  • avatar
    Mustangfast

    I guess “acceptable” was a relative term for reliability. I recall early 90s Chrysler minivans being all the rage, yet persistently suffering transmission failures. To this day it still affects my perception of quality with Chrysler.

  • avatar
    B-BodyBuick84

    Eh, I think weight had quite a bit to do with these transmissions failing. Growing up I had a friend’s father who had a 93 LeBaron with the Mitsubishi V6 and the 4 speed Ultradrive. Lotta things went wrong with that car, but the drivetrain wasn’t one of them. Not sure what kind of maintenance he did, but I know he sold it still running with over 180,000 miles.I think the size and heft of the minivans might have overstressed them.

  • avatar

    It is interesting if a book was written about these dramatic events. It would be an interesting read.

  • avatar
    SCE to AUX

    Pretty sure my 96 Grand Voyager (3.3) and 98 Grand Caravan (3.8) had the 41TE.

    The 96 never had a problem, and I faithfully changed the fluid every 25k, using the 7176 fluid. It’s not like it cost more money. The drivetrain in that car was excellent.

    The 98 needed a torque converter at ~120k miles, but I bought the car at 100k miles and didn’t know its history.

  • avatar
    Sled Dryvr

    A few comments on ‘UltraDive’….was working at a PentaStar plant in 1988 when the 4 speed was introduced. The story was that the VP for manufacturing was hyping this as the next best thing since sliced bread. In truth, the low CAFE numbers with the V6 minivans were pushing the 4 speed launch hard, more development was needed for this ‘clean sheet’ project. We launched in August 1988, then immediately went down a week because internal sealing rings (first large scale use of Teflon rings) were failing, followed by several ‘pauses’ as issues came up.
    My own experiences, a 91 Plymouth Grand Voyager AWD minivan failed at 110K, a 95 Dodge Grand Caravan AWD failed @ 99K, 2nd failed @ 104K, a Daytona & 2 Neons round out 5 for 5 failures. Have a last legacy, an 09 Journey, they made a 6 speed out of the 4 speed, 89K. Pedigree is not good, plus they have ditched the dip stick tube, you raise the car on a lift & check the lube level.
    My hope for Stellantis dims

    • 0 avatar

      I love firsthand background like this. Excellent.

    • 0 avatar

      The neon was a 3 speed torque flight for most of it’s run. The Ultrdrive didn’t come until 2003 I think. They got better at these as time went on. Failure rate dropped. I have owned a few 150k or more miles isn’t an issue with ones from the mid 90’s on usually. My parents did have a 92 or 93 New Yorker that was on transmission 3 by around 80k miles. Also got to keep in mind the average life span of a FWD auto from any brand in the 90’s was probably no more then 125k miles.

      • 0 avatar
        golden2husky

        mopar4wd – No so sure I’d agree with the statement that the average lifespan of a FWD trans was only 125K miles at the time. The three speed units in K cars were outstanding; from what I have heard they were A904 internals adapted to a FWD case. Mine went over 250K before the head gasket went and the trans still worked like new. And that was not unique to me. yes that was the 80s – perhaps the four-speed units were just more frangible…I also have the dreaded Ford unit in my 92…and it has over 237K on it and it still runs. I might just be lucky on that one however as there are plenty of horror stories with that one.

    • 0 avatar
      eng_alvarado90

      Thanks for the info.
      I guess that’s why Chrysler has phased out their in-house made transmissions on pretty much everything except for the HD trucks (which can have an optional Aisin anyway).
      Their ZF sourced 8 spd transmissions have been good, though. The 845RFE on my Ram is 276K miles. Just fluid and pan changes

  • avatar
    BobinPgh

    Why would a 4 speed automatic transmission need any electronics at all? Did having them increase fuel efficiency?

  • avatar
    eggsalad

    In the early 2000s I was driving a very rare stick shift 92 Voyager, a complete base model. The junkyards were full of the UltraDrive minivans, 99% due to failed transmissions. You could barely even find a rebuildable core by that time. It worked out well for me, though, because those vans were built like Lego, and I easily upgraded my van with lots of fancy parts from Grand Caravan and T&C vans.

  • avatar
    seisner53

    We had a 1995 Plymouth Voyager, swb, 3.3 engine (not the Mitsu 3.0). Regarding reliability, including the tranny, thankfully the service manager was a friend of my father-in-law. Blew first gearbox at 30k, second at 70k. Fixed bothe times, but never got clarification on cause. Then the electrical gremlins showed up, and that was the end of it.

  • avatar
    seisner53

    We had a 1995 Plymouth Voyager, swb, 3.3 engine (not the Mitsu 3.0). Regarding reliability, including the tranny, thankfully the service manager was a friend of my father-in-law. Blew first gearbox at 30k, second at 70k. Fixed bothe times, but never got clarification on cause. Then the electrical gremlins showed up, and that was the end of it.

  • avatar
    rizziriz

    I don’t agree with the comment that by 1991 there was acceptable reliability. I had a few Chrysler cars of that era and they all had many quality problems. These problems culminated with several trans problems with my 1994 Caravan. Everything broke on this car from the moment I bought it new. One time the trans locked up and a piece came through the case. Interior trim pieces cracked, radio broke, fog lights fell out, massive oil consumption (3.8L),cam and crank sensor, belt tensioner, fuel pump, starter all failed, more shall I go on !
    That’s when I started buying Hondas.

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