42RLE Poor Performance - Applies to ALL 4 speed owners - LOOK HERE!
This thread is intended to expose a flaw in the operation of Chrysler’s 4 speed 42RLE automatic transmission, as equipped in certain RWD, V6 equipped LX vehicles (Magnum, Charger, 300, Challenger).
**You have the 4 speed transmission (42RLE) if your vehicle is either the 2.7 or the 3.5, and you have the “PRND3L” shift gate. The 5 speed is used sporadically on the 3.5 RWD models, and is identifiable by the autostick shift-gate. If you have AWD, you have the 5 speed. If you have RWD and have auto-stick, you have the 5 speed. If your vehicle has the 5 speed, my posting here will not be relevant to you.
1. The Symptoms of the problem:
-Engine RPM’s feel as though they are not rising proportionally to throttle input. (MOST noticeable from 2500-3000 RPM, as well as off the line, but evident throughout the entire RPM range).
-Throttle response feels dead in certain instances (i.e. floor the gas pedal and acceleration feels to be severely lacking). Sometimes the car will chirp/spin the tires off the line and the RPM’s rise quickly, other times you can FLOOR the car off the line and get absolutely nothing.
-General sluggishness in acceleration
-Significantly increased DROP in RPM between shifts. (i.e. shifting from first to second or second to third when the vehicle is operating in this manner causes a greater drop off in RPM between shifts, leading to significantly reduced responsiveness.)
- This problem can occur in all weather conditions; however, it will be more noticeable in the hotter months of the year, in the spring/summer seasons.
-Throttle response will (sometimes) seem to vary on your daily drive (at certain points the car responds very “crisply”, other times it feels “boggy” (the car will usually feel “quick” or “strong” when it is first driven, such as in the morning after sitting all night). Throughout the day as you drive it, response may feel reduced.
-Take the car for a morning drive, let it fully warm up, then later on (preferably on a warm day), drive the car again, and you may notice the issue
2. The Problem:
The 42RLE transmission uses “EMCC” (an electronically modulated converter clutch). The way it is programmed to operate in this 4 speed transmission causes serious drivability issues (in some cases a SIGNIFICANT reduction in power and responsiveness). A torque converter clutch in an automatic transmission will lock/unlock at certain speeds, but the torque converter clutch in the 42RLE does not operate as Chrysler describes it in the owner’s manual. Read on to find out more.
3. The Proof: The 42RLE shift schedules can be found in the LX Service Manual PDF in section 8E-257. The following table is provided in the service manual; I have outlined the important parts.
To begin, the first four shift schedules, ranging from “Extreme Cold” to “Warm”, all state “No EMCC”. From my experience, when these shift schedules are used by the TCM, the vehicle responds perfectly to throttle input, and accelerates perfectly, with no dangerous hesitation or delay. As soon as the TCM resorts to using the “Hot” shift schedule (outlined in red), “Normal EMCC Operation” is employed. When this occurs, engine response feels reduced, acceleration is reduced, and the vehicle responds much worse than the driver would otherwise expect. This is a dangerous drivability issue. Furthermore, this scenario makes it seem as though the engine is the source of the problem. It has absolutely nothing to do with the engine at all.
Unfortunately for the driver, what is considered “normal” by Chrysler engineers can best be described as a considerable reduction in engine response during acceleration, which is very noticeable, and makes for dangerous situations where the user would expect the vehicle to “react” in a certain manner (i.e. in a passing situation), and the vehicle will not provide nearly as much accelerating power as when operating in the other shift schedules, where “EMCC” is not used. This should not be a problem, as Chrysler claims that the torque converter clutch will disengage under acceleration. Unfortunately, based on my testing, the converter clutch may only partially disengage (PEMCC). I know this based on engine RPM (full disengagement yields slightly higher RPM at a given speed than does partial disengagement. In cases where the TCC does fully disengage, you will notice a slight jump in engine RPM (compared with partial engagement)
The most important thing to notice here is the fact that the “HOT” shift schedule has the largest temperature range, and will likely be the shift schedule used by the TCM in most driving conditions. This would not be a problem if the TCC was sensitive enough to fully disengage under acceleration.
The temperature range, for the “Extreme Cold” to “Warm” shift schedules, where “No EMCC” is used, is from -16 degrees Fahrenheit up to 80 degrees Fahrenheit. This temperature range is small in contrast to the temperature condition for the “Hot” mode of operation, which operates from 80 degrees Fahrenheit all the way up to 240 degrees Fahrenheit. In other words, this is the shift schedule that will most often be used, and it will result in “Normal EMCC operation”.
Here is the definition which Chrysler provides for the “Torque Converter Clutch” for the 4 speed automatic transmission (p. 212 of the Owner’s manual in PDF form, available online here: My Chrysler: Chrysler Owners Service Manuals - Chrysler Cars, Minivans, SUVs, Convertibles, Crossovers). I have highlighted the important parameters.
“Torque Converter Clutch
A feature designed to improve fuel economy has been
added to the automatic transmission of this vehicle. A
clutch within the torque converter engages automatically
at calibrated speeds. This may result in a slightly different
feeling or response during normal operation in high
gear. When the vehicle speed drops or during acceleration,
the clutch automatically and smoothly disengages.”
The description would seem typical of any automatic transmission, as most automatic transmissions that I am aware of use a lockup torque converter to save fuel and lower RPM’s at highway speeds. If Chrysler’s operating definition provided in the Owner’s Manual was in fact accurate, it would leave no reason for the driver of the vehicle to be concerned. However, my testing has revealed that what Chrysler considers a “slightly different feeling or response during normal operation in high gear” is actually a CONSIDERABLE REDUCTION in response in not only high gear (4th), but also first, second, and third gear. Interestingly enough, in Chrysler’s definition of the TCC in the owner’s manual, they state “high gear”. Of course, this leads to some ambiguity: what do they really mean by “high gear”? If they meant 4th, I think they would’ve stated “overdrive” or something similar.
Chrysler also states (in the Owner’s Manual) that “When the vehicle speed drops or during acceleration, the clutch automatically and smoothly disengages”.
This description is also inaccurate; in my testing (up to WOT) this clutch fails to fully disengage in many circumstances (when the TCM is using the “HOT” shift schedule), and in fact remains engaged in a partial state (PEMCC).
When the clutch remains partially engaged, rather than fully disengaged, acceleration feels considerably slower. There is less of a "pull" sensation. This has mistakenly been diagnosed as an engine issue due to hot weather, low octane fuel, etc. It does happen more often in hot weather, but it has nothing to do with the engine making less power.
Here’s an interesting piece of information I uncovered in the LX Service manual, which would seem to directly contradict the operating parameters Chrysler gives in the Owner’s Manual. (21-361 of the Service manual).
“Theory of Operation
When in 2nd, 3rd, or 4th gear, the torque converter clutch (TCC) can be locked or partially locked when certain
conditions are met. The TCC piston is electronically modulated by increasing the duty cycle of the LR/TCC solenoid
until the torque converter slip difference (difference between engine and turbine speed) is within 60 RPM. Then the
LR/TCC solenoid is fully energized (FEMCC / 100% duty cycle). Torque converter slip is monitored in FEMCC to
ensure adequate clutch capacity. The transmission will attempt normal EMCC operation (not in Limp-in) even after
the MIL is illuminated. MIL will illuminate after 5 minutes of accumulated slip in FEMCC.”
To sum it up: When the TCC is disengaged, it is "slipping" which allows heat to build up more quickly. Thus, when you are in "steady state" driving, or under very light acceleration, the TCC will remain fully or partially engaged. This is desirable and normal. I am not disputing this. What is not normal is the fact that it does not fully disengage in many circumstances, including at WOT.
Due to the way that this transmission is programmed to operate, on more than one occasion, I have found myself coming to a FULL STOP on highway entrance ramps in this vehicle due to the fact that it will not accelerate in the manner I expect it to. This means that, when the torque converter clutch does not fully disengage under acceleration, the vehicle has considerably less acceleration, even at wide open throttle, and can make for driver and passenger ENDANGERMENT specifically because the performance of the vehicle is DRASTICALLY inconsistent, and varies sporadically.
In my searching of the various LX forums, I have found users complain about symptoms which I had (in the 4 speed), but they seemed unaware as to what caused the issue; they thought that hot weather had something to do with it (which is partially true) or that it could be fixed with tuning or programming, such as the Diablo Predator (not true).
Chrysler should be notified about this problem, and should be forced to resolve it. A simple TCM reflash with updated parameters for TCC engagement would solve the problem. If it operated as they describe in the Owner’s manual, there would not be a problem. Unfortunately, this is not the case. The 300 touring with v6 is a good vehicle, and if Chrysler fixed this issue, it would be much better.
4. Other owners experiencing this problem:
torque loss after few miles
Dodge Charger SXT 2010 charger v6 3.5 4 speed 5000 miles - JustAnswer
3.5 feels sluggish - Horsepower Loss? - Dodge Charger Forums
Slow Throttle Response
42RLE (4-Speed) Symptom & Solution
**I was able to locate a thread on chargerforums.com which was supposedly started by one of the 2 “engine calibrators” that worked on the 3.5l LX platform. If this is true, and if we can contact this individual, perhaps they have insight into this issue. (Although the posting is originally from 2006).
3.5L LX Complaints here's your chance [Archive] - Dodge Charger Forums
5. Video Proof
Car Acceleration Properly: Running Properly - YouTube
Car Accelerating Poorly: Running Poorly - YouTube
New WOT videos:
No EMCC (Running Properly) - http://youtu.be/yI_Sj5FRFo4
EMCC (Running Poorly) - http://youtu.be/1nP85-g7Q2k
(Please Note: The two cars used in the making of the EMCC (Running Poorly) video are NOT mine, they were simply selected to demonstrate the issue that all 4 speed LX vehicles have. This is exactly the way my car behaves in the heat of summer). The difference in performance is quite drastic.
6. Final Thoughts:
The Diablo Predator tune does nothing for this issue; I purchased one Diablo Predator (brand new), and loaded the 91 octane tune onto my vehicle. After driving for a while, when the vehicle is fully warmed up, the TCM will resort to the same unresponsive shift schedule, and not fully disengage the torque converter clutch under acceleration (even though Chrysler says it should).
Chrysler has released a TCM update for their 90's LH vehicles (Concorde/Vision/Intrepid etc) which addresses an issue with the 42LE transmission, in part related to sluggish acceleration due to the fact that the TCC "may not disengage as desired". This is eerily similar to the issue that I am suggesting. If you care to examine the TSB, it can be found here: http://www.robskorner.info/faqs/TSB/18-24-95.pdf (see page 2, item # 3).
"It's a v6 it's supposed to be this slow" type of comments will be ignored. It's not a FAST car but there is no reason for it to be this unresponsive, especially considering that I have experienced plenty of good acceleration when the EMCC fully disengages.
Last edited by 4 speed owner; 04-14-2013 at 05:44 AM.
speaking of TCM rewrite, Has the stealerships made an update for it? I know my charger needed a pcm update and it helped alot from my butt dyno. Other then that I don't want to be a snob but a v6 in a 2+ ton tank with a eco automatic should be sluggish not banging off the line for the rental car companies and family sedan.
Chrysler doesn't have a TCM update that fixes this problem. When I had the transmission fluid changed at the dealer, they flashed the TCM with the latest update but it still behaved the same way.
The thing is, it's not sluggish at all when the torque converter clutch is disabled - I just want it to be that way all the time (with the 4 speed). The 5 speeds don't do this at all.
LE/RLE/TE EMCC release strategy is much different at part throttle than it is at WOT.
at WOT, EMCC disengagement is instantaneous, while at part throttle, disengagement is gradual.
this is done by modulating the LR/CC solenoid duty cycle in order to soften the change from full or partial EMCC to no EMCC.
not sure if it's available for the 4 speed guys but DiabloSport Predator's throttle boost feature may help by opening the throttle wider than accelerator pedal position would normally dictate.
btw, welcome to LXforums.
i wish they never would have taken away the vehicle profile from post headers.
Well that makes perfect sense.
Originally Posted by fnkychkn
FRI Econo Heads & FRI Sidewinder: Installed @ BFNY by Hemi31 with special guest Fnkychkn, JBA Shorties, JBA/HHP hi-flow catted mids, stock SRT8 cat-back, C&L CAI.
HUGE thanks to Hemiwagn and HalfFast Performance for making it all possible.
Hello, Thank you for the welcome. I've driven this car for three years and it doesn't matter whether you are at WOT or not. I was simply showing in my videos at 80% throttle so that it wouldn't kick down into first. Even at WOT (pedal to the floor) EMCC sometimes does not disengage under the "HOT" shift schedule.
Originally Posted by fnkychkn
I also used the Diablo Predator with throttle boost feature and it made no difference. Yes, the Predator made the engine a little louder and tuned it to run on 91 octane fuel, but the TCM was still controlling the shift strategies and therefore I was still experiencing this problem.
EMCC should disengage fully under acceleration. From a roll on 60 km/h in second gear, I can FLOOR it and it does not disengage at all. Sometimes if I BEAT THE HELL out of the car (completely unecessary) and ride it out to 6500 RPM in 1st gear 10 times, it will finally disengage, and from that point onward (assuming I don't shut off the car) it WILL disengage in 2nd gear from a roll going WOT. The "pull" is much harder when it does this, and the RPM's are slightly higher compared to partial engagement. It is very slight and most people won't notice it, and they will think their car is functioning normally.
Edit: Post updated to include WOT videos showing the difference between EMCC and no EMCC.
Last edited by 4 speed owner; 04-13-2013 at 02:03 AM.
Reason: Added video links
from a standing start at WOT, EMCC should not be active until accelerator is backed off from WOT, regardless of engine/trans temp.
noticed in the first WOT link i couldn't see coolant temp guage. any chance you can post another video showing coolant temp in EVIC?
you may want to get your dealer to install a data recorder to monitor;
- coolant temp
- trans fluid temp
- ambient temp
- spark timing
- injector pulse width
- engine RPM
- vehicle speed
- actual gear
- EMCC state
- pressure switch states
- anything else they feel may be relevant
Last edited by fnkychkn; 02-20-2012 at 04:43 PM.
Reason: more info
That WOT run was done a while ago. I did it after driving the car for a while, and remember the coolant temp gauge being right at slightly below half (where it usually sits when the car is fully warmed up). Of course, I will be happy to shoot another video showing the gauge as well as EVIC temp. (I didn't shoot that WOT vid for the purposes of showing EMCC being disabled, it was just for my own fun).
Of course, when I had my Predator, the intent was to do data-logging to show how the car drives differently relative to trans. fluid temp, but I ended up selling it because it did not fix my problem (wanted to get my $$ back).
Having said that, do you know why Chrysler has a "Hot" shift schedule in the first place? I know in the manual the stated goal of the TCC is to improve fuel economy, but I don't know why EMCC would not be active under a "Warm" shift schedule, if indeed it does improve fuel economy.
In the cold weather up here in Canada in the past couple of months (below 0 celsius) I have been able to drive the car around for an hour and during that whole time not once did I feel EMCC kick in. Whether at part or full throttle it was always unlocked, every single time. My guess is that the TCM was using the "Warm" shift schedule which specifies "no emcc".
I'm just a little confused as to why the 4 speed has this type of lock-up once the trans. fluid reaches a certain temp. Could it be for longevity reasons for the trans?
For the record I replaced the v6 300 (still have it though) with a 2010 300c. My brother also has a 2009 300c and neither of these vehicles with the 5 speed behave anything like the 4 speed. The 300c's accelerate and behave the same way all the time, regardless of exterior temperature or throttle position.
I guess this would be a question for the Diablo tuning guys, but if they could possibly update the TCM in such a way that the "Hot" shift schedule behaves the same as when "Warm", I would be a happy camper.
Last edited by 4 speed owner; 02-20-2012 at 05:06 PM.
Canada, you say?
if you're ever in ottawa, look me up.
btw, that shift schedule has been in effect for many years. way back to the 604, IIRC.
Thank You Haz
I had a 2000 Caravan 3.3 with 4 speed 41te transmission, I drove that for many years as well, and it did not behave the way that my 300 with the 4 speed is behaving. Obviously the Caravan was slow, but performance was always consistent; it never changed the way the 300 does.
Also, just for kicks, I downloaded the manual for the 2004 Chrysler 300m just to take a look through the transmission section - nowhere does it have a section with the "torque converter clutch" that is found in the 2005-up LX manual. Just thought that was kind of interesting.
how much horsepower can these transmissions handle?? also is there anything a predator or intune can do to solve these issues?
I can't answer your first question as I'm not exactly sure. In regards to your 2nd, the Predator/Intune does nothing for this torque converter clutch issue, because they do not have a program for the TCM specifically. I'm not sure if they are able to program for the TCM/adjust lock-up, but at this point the Diablo tune does nothing for this issue. The Predator does nothing for the 4 speed TCM.