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Discussion Starter #1
well, i finally got some dry pavement and got to step on her a bit. problem was that at about 60 mph i went to pass a car and when i floored it i got instant response for a second then it seemed the tranny kicked out for a second or two then engaged again. is this normal? i tried it several times today and each time the same thing. i hope nothings wrong but if anyone has any ideas on this i still have full warranty. thanks
 

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could it be torque converter problems? i would definitely take it in and have it looked at. you still have your warranty so get it taken care of! :)
 

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Our transmissions and throttle response have all sorts of hesitations and bogging built in. Not sure if your's is normal, or something more serious.
Take your dealer for a ride and demonstrate the lag. Most likely all they will do is flash your TCM, and maybe PCM, to the latest version.
 

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My car never had any transmission lag whatsoever, and it is definitely not normal. The shifts were too soft, and the autostick had some delay, but that is not what you describe. Both of these issues were corrected by the flashpaq; but there wasn't anything wrong with my car - - I just prefer the firmer shifts.

Is it possible you are feeling a slow throttle response and mistaking that for a transmission problem? there is a procedure to re-set the electronic throttle if that's the culprit. Try this before you take it in:

Procedure: To overcome hesitation at acceleration- for the 5.7L Hemi V-8

1) Turn key to ON position (not ACC), but DO NOT start engine.... now wait a few seconds for the dash lights to clear


2) slowly & steadily press accelerator pedal all the way to the floor and then slowly release at same rate.
NOTE: This step must be done ONE TIME only to ensure accelerator pedal position sensor calibration has been
learned by the ECM

3) Leave ignition switch ON for a minimum of 10 seconds. This will allow the PCM to learn the new electrical parameters
 

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Discussion Starter #6
i'll give that a try kevinj but it is definitely not a slow throttle response. the lag is slow enough ( about 2 seconds) it makes you think twice about passing. ( is it gonna go - anytime now. lol
 

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i'll give that a try kevinj but it is definitely not a slow throttle response. the lag is slow enough ( about 2 seconds) it makes you think twice about passing. ( is it gonna go - anytime now. lol
something definitely wrong then, cuz with my Hemi I NEVER have to think twice about passing if it's even remotely prudent:biggrin:

Hopefully it's not an intermittent problem so you can demonstrate to the service writer what its doing and avoid the whole "Can't duplicate problem" routine. Good Luck!
 

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i'll give that a try kevinj but it is definitely not a slow throttle response. the lag is slow enough ( about 2 seconds) it makes you think twice about passing. ( is it gonna go - anytime now. lol
When I get into some intense driving situations, I often make a quick throttle pump/release just before I think I am going to WOT. This eliminates all the tranny/throttle hesitation. Everyday I make it a challenge to see how to avoid throttle/tranny lag.
 

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When I get into some intense driving situations, I often make a quick throttle pump/release just before I think I am going to WOT. This eliminates all the tranny/throttle hesitation. Everyday I make it a challenge to see how to avoid throttle/tranny lag.

I've never experienced anything like what you are talking about;

What exactly do you mean by "Lag"? Are you guys saying that you're cruising along in Drive (5th gear) and you floor it and the transmission doesn't downshift? or it only downshifts to 4th when you think it should go to 3rd?

It could be as simple as a software flash to correct; I'd definitely take it in and get it checked out. What the hell is the point in having a 340 hp V8 if you can't even pass a slow moving vehicle or merge into traffic?

As I said before, my transmission's performance is much improved (and shifts are much more "instant" ) with the Superchips flashpaq - - but even before I had the flashpaq If I stepped on the pedal, she'd downshift and take off like a Hemi should! The only thing I experienced before the flashpaq that I could call a "lag" was the delay when manually shifting in "autostick" mode. That is gone now with the flashpaq.

Hope you get it resolved.
 

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When I get into some intense driving situations, I often make a quick throttle pump/release just before I think I am going to WOT.
That sounds like a good way to completely confuse the computer and ultimately cause some transmission damage:pat:
 

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Everyone has their own definition of hesitation or bogging.
There can be hesitation/bogging off the line from a full stop, hesitation/bogging between shifts under full throttle conditions, there can be hesitation/bogging under light and/or modulating throttle. There might even be more situations.

Where I find the major annoyance is the third condition, hesitation/bogging under light and/or modulating throttle.
This hesitation/bogging can occur on the freeway, or driving around town.

Here is an example of the hesitation/bogging under street driving conditions
using flashpaq data logging.

I am accelerating from a stop up to 33kph (20mph) and RPMs reach 2,954, and throttle position reaches 30%, I then quickly let off the throttle for a fraction of a second and throttle position drops from 30% to 29%.
RPMs also drop from to 2,954 to 2,919.

Everything is normal up to this point.

Then I step on the throttle again and throttle position increases from 29% to 31% and 32%.
RPM's should start to increase as I step on the throttle, right?

Wrong. Here is were the hesitation/bogging occurs.
Instead of the RPM's increasing as I apply more throttle, the RPMs start to drop from 2,919 to 2,489 and 2,488.

This drop in RPMs, while I am applying throttle, is clearly felt as a hesitation/bogging feeling.
A drop of 430rpms in slightly over half a second is a lot. My only guess it is caused by the torque converter.

 

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I've never experienced anything like what you are talking about;

What exactly do you mean by "Lag"? Are you guys saying that you're cruising along in Drive (5th gear) and you floor it and the transmission doesn't downshift? or it only downshifts to 4th when you think it should go to 3rd?

It could be as simple as a software flash to correct; I'd definitely take it in and get it checked out. What the hell is the point in having a 340 hp V8 if you can't even pass a slow moving vehicle or merge into traffic?

As I said before, my transmission's performance is much improved (and shifts are much more "instant" ) with the Superchips flashpaq - - but even before I had the flashpaq If I stepped on the pedal, she'd downshift and take off like a Hemi should! The only thing I experienced before the flashpaq that I could call a "lag" was the delay when manually shifting in "autostick" mode. That is gone now with the flashpaq.

Hope you get it resolved.
We were posting at the same time.

I did take my car to the dealer and complain. They flashed my car, but it didn't change the shifting behavior. I have seen numerous other threads on shift hesitation/bogging, so it is a known problem with our cars.
I have flashpaq and it doesn't change or reduce the hesitation/bogging as I described in my previous post.
 

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Discussion Starter #13
what it feels like is at any speed when i hit the gas it seems it kicks in to pass then kicks out in about a second then theres a delay of about 2 secs ( downshifting?)before it finally throws you back and takes off like it's supposed to. i am going to try the accelerator adjust and will see if it does it with auto stick in fourth also. i also have flashpaq ( have not played with it much yet due to winter) so maybe i can find something there to make it better. i am taking the car to the dealer soon to have the wheel issue looked at so could get them to look at that too
 

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Then I step on the throttle again and throttle position increases from 29% to 31% and 32%.
RPM's should start to increase as I step on the throttle, right?

Wrong. Here is were the hesitation/bogging occurs.
Instead of the RPM's increasing as I apply more throttle, the RPMs start to drop from 2,919 to 2,489 and 2,488.
What you are feeling is the torque converter locking up; it is perfectly normal and is NOT a problem with your transmission. It is doing what it's supposed to do!

when you let off the gas like you describe, your torque converter unlocks. As you slowly depress the accelerator the torque converter begins to lock up
(less slippage, which reduces heat and is more efficient) and that's why you see the RPM actually drop slightly as the throttle postition increases. The torque converter in our transmissions is a 'gradual' or 'variable' lockup type, meaning it isn't just "locked" or "unlocked" as the lock up converters of the 80's and 90's. Modern torque converters gradually lock up or unlock so you don't feel it as much as on the older trannys, but you can still see it in the Tach. On the older trannys with lockup converters (like the 700R4 I had in my 87 Firebird Formula 350) the lockup converter was so obvious it sometimes actually felt like the transmission was shifting gears. Modern trannys have tried to eliminate this by making the lockup gradual. That's all you're seeing.

If you were cruising at a steady speed and then floor it, it will downshift and go like hell, because the torque converter isn't going to start to lock until you are back at a steady cruising speed.
 

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Don't forget to throw MDS into the mix for the non SRT8 owners. No matter how "good" anyone makes an MDS system there is still a measureable amount of time for the selonoids to close, restablish oil flow to the disabled lifters and to turn on the fuel and spark for the deactivated cylinders. If you are cruising at say 9/10% throttle and as you apply throttle the TC may need to lock and the MDS needs to deactivate, and this is all measureable (albeit they say the changeover for MDS is in the 40 millisecond range I beleive?)
 

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What you are feeling is the torque converter locking up; it is perfectly normal and is NOT a problem with your transmission. It is doing what it's supposed to do!

when you let off the gas like you describe, your torque converter unlocks. As you slowly depress the accelerator the torque converter begins to lock up
(less slippage, which reduces heat and is more efficient) and that's why you see the RPM actually drop slightly as the throttle postition increases. The torque converter in our transmissions is a 'gradual' or 'variable' lockup type, meaning it isn't just "locked" or "unlocked" as the lock up converters of the 80's and 90's. Modern torque converters gradually lock up or unlock so you don't feel it as much as on the older trannys, but you can still see it in the Tach. On the older trannys with lockup converters (like the 700R4 I had in my 87 Firebird Formula 350) the lockup converter was so obvious it sometimes actually felt like the transmission was shifting gears. Modern trannys have tried to eliminate this by making the lockup gradual. That's all you're seeing.

If you were cruising at a steady speed and then floor it, it will downshift and go like hell, because the torque converter isn't going to start to lock until you are back at a steady cruising speed.
I agree that the torque converter is the most likely culprit. But I don't agree the hesitation/bogging is acceptable, or should be considered normal. None of my other cars have ever bogged down when I stepped on the peddle. I don't know if the problem is from the new modern design of the lockup torque converter, but what ever it is, it has changed the performance of the car for the worse. I am always fighting with the hesitation/bogging and trying to find ways to avoid it. It is one of the major faults in the car, IMO.
 

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I agree that the torque converter is the most likely culprit. But I don't agree the hesitation/bogging is acceptable, or should be considered normal. None of my other cars have ever bogged down when I stepped on the peddle. I don't know if the problem is from the new modern design of the lockup torque converter, but what ever it is, it has changed the performance of the car for the worse. I am always fighting with the hesitation/bogging and trying to find ways to avoid it. It is one of the major faults in the car, IMO.
If you are actually noticing it to the point that it's detrimental to the way the car drives or if you even think about it really, the you are feeling something completely different than the normal torque converter lockup. What has the dealership said? Have you driven other 300C's? I wish I could drive your car so I know exactly what you're feeling. I'm not one of these people who drive around blissfully unaware of what his car is doing; I guarantee you I'm much more "in tune" to these kinds of things than is the average driver, and I have NEVER felt my car do anything like what you describe, even before I had the flashpaq. Vague shifts in automatic mode and a definite time lag in autostick (a delay between when you move the lever and when it would actually shift) were my only complaints pre-flashpaq. Certainly not any kind of hesitation or "bog". I've actually been pretty impressed with how well this transmission performs overall.

Do you have aftermarket wheels on your car that may be considerably heavier , or perhaps taller overall, than the stock wheels? Extra unsprung weight could be a contributor, and of course if your wheels are taller overall that has the effect of higher gearing, which would make the engine "lug" or "bog" more easily. If you do have aftermarket wheels the first think I'd do is put the stockers back on and see if you still feel this "bog". Another possibility is an engine misfire which could be mistakenly interpreted as a transmission malfunction. Hope you get it figured out!
 

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Keven,

Since you are "in tune" with what your car is doing. When you are on the highway and MDS is on, do you notice the time lag it takes to fully reactivate the cylinders? Just curious (I notice it on my 07 and it's not that this is a bad thing, it's just how much I pay attention to what my engine and driveline is doing) there are times where I just drive around and listen and feel what the car is doing.

The Autostick lag is something I experiance and that's annoying, my previous AS cars didn't have the lag that the 300 does. Of course the other cars wern't luxury so I'm sure DCX at the time programmed it to be smooth rather than fast and abrupt. Glad to hear the flashpaq took care of that, hope the Diablo Predator does it as well.
 

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Keven,

Since you are "in tune" with what your car is doing. When you are on the highway and MDS is on, do you notice the time lag it takes to fully reactivate the cylinders? Just curious (I notice it on my 07 and it's not that this is a bad thing, it's just how much I pay attention to what my engine and driveline is doing) there are times where I just drive around and listen and feel what the car is doing.

The Autostick lag is something I experiance and that's annoying, my previous AS cars didn't have the lag that the 300 does. Of course the other cars wern't luxury so I'm sure DCX at the time programmed it to be smooth rather than fast and abrupt. Glad to hear the flashpaq took care of that, hope the Diablo Predator does it as well.
I have never been able to discern when MDS is on or off, or when it's switching from 8 to 4 cylinders. My '05 does not have an indicator light as (I believe) the '07's do. If I had a light telling me when it's on or off I might be able to convince myself that I could feel something happening, but I honestly can't tell. I've never heard anyone actually say they could tell unless they had aftermarket exhaust where you can hear the difference. I have an '07 Ram 4x4 quadcab Hemi with MDS and I can't tell when it activates either. I know it works though because I only get 12 mpg in town with the truck but I can get 19 on the highway at 70 mph (according to the mileage calculator in the truck). My truck has stock quiet exhaust too so I can't hear any teltale 'drone' with the cylinders shut down.

I suspect (but don't know for sure) that in the 300C MDS doesn't work above 80 mph; I know there are many criteria for when it engages or doesn't engage. But the reason I suspect a "cut off" at 80 is last fall I took a long road trip, and on one particular day put on about 600 miles on Interstate 90 across Wyoming and into South Dakota. I had the EVIC set to average MPG, and if I set the cruise control at 79 mph my average MPG would steadily increase... up hills, down hills, head wind, really didn't seem to matter..... MPG's would slowly increase until the display showed 23...23.1..... and hold steady. If i increased my speed to 81 mph however, the MPG's would start to slowly decline...... a tenth at a time..... til it was showing down around 19.7....19.8.....and hold steady there. Slowing back down to 79 the MPG's would start to increase all over again. I repeated this excercise a couple times thru the day to make sure I was not imagining it, and there definitely is a "line" there at 80 as far as gas mileage goes. It just seemed too arbitrary to be anything else than MDS not working above 80.

Oh....... then there was the little 5 mile jaunt with the cruise sitting on 110, followed by a run up to just a little over 140 before I settled back into my comfortable 79 mph cruise control setting....... I think the EVIC was showing something like 14 MPG after that little run!
 

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I have not been looking at any MDS indicator when I feel it. (I actually don't have an MDS icon unless I dive into the easter egg and display the performance/mpg meter the 08's are able to display an MDS icon in the default evic opening page). I feel it ever so slightly on mine (and I do mean ever so slightly).

I would tend to agree at 80 you wouldn't see MDS functioning. I don't know that it would be that MDS is disabled at XX speed or something to the effect that it may take more than 10% throttle to maintain 80MPH even on flat land (we are after all, driving a brick) If the Drag Coefficient was lower at 80 MDS may still be enguaged. Just a hypothesis.
 
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