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Discussion Starter #1 (Edited)
I bought a 2008 300C SRT8 last November, and overall I have been very happy with it. The only thing I'm not happy with is the transmission. It is very inconsistent. I would like to know if anyone else has had these problems I'm experiencing and if the dealer should be able to fix them.

The biggest problem for me is the 1-2 upshift. There is never any hesitation, but sometimes it shifts way before redline during WOT, even as low as around 5500 RPM. I thought that using autostick was supposed to make it hold gears until redline, but this doesn't work either. For a while, I thought it was, but that doesn't work consistently. For example, when I slap it into first using autostick and mash the throttle, it still shifts way before redline sometimes, regardless of whether or not there is any wheelspin at the time. Sometimes the 1-2 shift occurs at or near redline during WOT, but I want it to always shift at or near redline. The 2-3 and 3-4 upshifts always occur very, very close to redline during WOT, so there is no problem with those shift points, just the 1-2 shift.

Another problem is the downshifts. I understand that the SRT8 has an adaptive transmission, but it seems that it lacks consistency. Sometimes I get downshifts when I expect them, and sometimes I don't. I can start driving it really hard for some time, and not get the downshift when I want it while at other times I can cruise around town slowly for a while in traffic and get the downshift later when I want it. On the bright side, at least the autostick can be used to get the downshift, but I don't like having to do that all the time.

Has anyone else experienced these problems with the SRT8 transmission? Can the dealer fix the problems? I hope the problems can be fixed without an aftermarket programmer. I've heard about the Diablo Predator, but I want to get it working right without tinkering with an aftermarket programmer. Please, please, please tell me the SRT engineers didn't make my car like this "on purpose".
 

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Apparently 2007+ vehicles have updated software (that 2005-2006 vehicles need a flash to get) which is supposed to provide better shifting in D and "perfect" shifting in AS, meaning it will auto shift for you at the "optimum" RPM so you don't over-rev the engine. This means no gear holding and is the reason some 2005-2006 owners don't get the TSB flash (irreversable) done.

See post #2 in the following thread: http://www.300cforums.com/forums/srt8-specific-general-discussion/40760-update-srt8-shifting-before-6200-1st-autostick.html?highlight

=shift+5500


Link for the 2005-2006 trans. flash TSB:
http://www.300cforums.com/forums/sr...8-1-2-delayed-shift-solution-has-arrived.html

BTW, I got the flash done and the shifting in D seems to have improved quite a bit. There were a few stumbles yesterday but I think that was because of ESP activating due to my heavy foot.:biggrin: Try a pull of fuse 11 and test out the shift consistency then.
 

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Discussion Starter #3
Please, somebody bump this topic so I can get some advice. So far it appears that only one person on this forum is experiencing my problem. Even if you are not experiencing the problem, just let me know. I am VERY DISATISTISFIED with the SRT8 transmission and it is really pissing me off! I want consistent 1-2 shifts!

I read through that first thread, and that guy seems to be having the same problem I have, but I cannot find anyone else having the problem where it shifts way before redline (recently it seems like it short-shifts about 50% of the time). I have an 08 so it has the upgraded flash for the transmission, but does not work the way it is described in the TSB thread.

I read through the first 10 pages of the TSB thread, and it sounds like nobody there is having the problem I'm having. (I really don't want to read all 20+ pages of that thread.) Everyone there seems to be reporting that it holds gears until redline when using autostick, which is definitely not the case with my car. In addition, the transmission behaves in the same inconsistent manner in Drive mode at WOT on the 1-2 upshift. It NEVER short-shifts on the 2-3 or 3-4 upshift, regardless of if I'm in Drive or Autostick mode, so why does it short-shift on the 1-2 upshift? I know this is hurting my performance because I can feel it pulling real hard and then BAM, it shifts too soon and the RPMS drop far lower than they should due to the early shift.

The dealer better be able to fix this problem because I'm getting really frustrated at this point! If they can't fix this problem, I may never buy another Chrysler product, sad to say.

Apparently 2007+ vehicles have updated software (that 2005-2006 vehicles need a flash to get) which is supposed to provide better shifting in D and "perfect" shifting in AS, meaning it will auto shift for you at the "optimum" RPM so you don't over-rev the engine. This means no gear holding and is the reason some 2005-2006 owners don't get the TSB flash (irreversable) done.

See post #2 in the following thread: http://www.300cforums.com/forums/srt8-specific-general-discussion/40760-update-srt8-shifting-before-6200-1st-autostick.html?highlight

=shift+5500


Link for the 2005-2006 trans. flash TSB:
http://www.300cforums.com/forums/sr...8-1-2-delayed-shift-solution-has-arrived.html

BTW, I got the flash done and the shifting in D seems to have improved quite a bit. There were a few stumbles yesterday but I think that was because of ESP activating due to my heavy foot.:biggrin: Try a pull of fuse 11 and test out the shift consistency then.
 

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Ken, I think the problem here is that there's not a lot of owners of 2008 SRT8's to compare with yet. I never did get the flash for the reason I want to be able to hold a gear. That TSB eliminated it permanently. Many swear by it, but there are a few like me who don't want it. The problem as I understand it is that the tach lags slightly behind. You now upshift at a lower rpm before it bounces off the engine limiter, which is where the 1-2 hesitation came from.

I think the only thing you'll be looking at is the Predator if you want to see any improvement.

Bernie
 

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I bought a 2008 300C SRT8 last November, and overall I have been very happy with it. The only thing I'm not happy with is the transmission. It is very inconsistent. I would like to know if anyone else has had these problems I'm experiencing and if the dealer should be able to fix them.

The biggest problem for me is the 1-2 upshift. There is never any hesitation, but sometimes it shifts way before redline during WOT, even as low as around 5500 RPM. I thought that using autostick was supposed to make it hold gears until redline, but this doesn't work either. For a while, I thought it was, but that doesn't work consistently. For example, when I slap it into first using autostick and mash the throttle, it still shifts way before redline sometimes, regardless of whether or not there is any wheelspin at the time. Sometimes the 1-2 shift occurs at or near redline during WOT, but I want it to always shift at or near redline. The 2-3 and 3-4 upshifts always occur very, very close to redline during WOT, so there is no problem with those shift points, just the 1-2 shift.

Another problem is the downshifts. I understand that the SRT8 has an adaptive transmission, but it seems that it lacks consistency. Sometimes I get downshifts when I expect them, and sometimes I don't. I can start driving it really hard for some time, and not get the downshift when I want it while at other times I can cruise around town slowly for a while in traffic and get the downshift later when I want it. On the bright side, at least the autostick can be used to get the downshift, but I don't like having to do that all the time.

Has anyone else experienced these problems with the SRT8 transmission? Can the dealer fix the problems? I hope the problems can be fixed without an aftermarket programmer. I've heard about the Diablo Predator, but I want to get it working right without tinkering with an aftermarket programmer. Please, please, please tell me the SRT engineers didn't make my car like this "on purpose".
As for inconsistent down shifts I know you have to back off to a neutral throttle position before it will let you have a lower gear in auto stick mode. Quite inconvenient with the 25 MPH kickdown limit in drive. Alot of times a slower car will kick my ass if i don't get into first gear before running from a 26 MPH+ punch. Trick is to get the thing into gear early so you are not too low in the power band. My old 95 lincoln town car ( 210 HP )will beat my SRT 8 from a 26 MPH punch (in drive) for a few seconds. As for your list of problems I've seen my SRT 8 do alot of weird things that don't make me too happy.
 

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Ken,
I'm afraid that's the nature of the beast with our adaptive transmission. A few WOTs in a row shift it at redline, the predator completely solves it I've heard, and pulling fuse 11 solves the problem right away too. I'm hopefully picking up my Predator and getting a CMR tune today. I've read but cannot verify that the '08 fuse boxes are a little different, so the pulling fuse 11 trick may not be so simple for you, I read there's another way that's as easy on the '08s but you'll have to search for it. Good luck,

Eric
 

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Ken,
I'm afraid that's the nature of the beast with our adaptive transmission. A few WOTs in a row shift it at redline, the predator completely solves it I've heard, and pulling fuse 11 solves the problem right away too. I'm hopefully picking up my Predator and getting a CMR tune today. I've read but cannot verify that the '08 fuse boxes are a little different, so the pulling fuse 11 trick may not be so simple for you, I read there's another way that's as easy on the '08s but you'll have to search for it. Good luck,

Eric
Eric, it's now fuse #2 for the 2008's. I agree though, pulling it from time to time will help. These cars are fast learners!

Bernie
 

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The best way to fix these issues is to get the Diablo Predator tuner. The Diablo tuner raises the shift points to 6400rpm in every gear and raises the kickdown point in first gear to about 35mph. These changes alone made a huge difference in driving around town. By the way, if you don't want to install the tune that comes with the diablo tuner, you can still use it to modify just your shift points on your stock tune.
 

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Discussion Starter #9 (Edited)
Thanks for all of your advice guys. I really appreciate you taking the time to respond to my questions. I guess I have a few choices, Predator, fuse, and possibly a dealer repair/reprogram.

The downshift in Drive isn't that bad because I can always use autostick to downshift. The random premature 1-2 shift during WOT in autostick (and Drive) is what really bothers me, and I'm certain it's not the analog tach readout just lagging behind the actual engine revs. I know when it's time to shift based on the way the engine sounds and the way the car is pulling, and it definitely is not shifting at the right time on some runs. It's still making more power prior to the shift and the worst part is that I have absolutely no control over the shift. (Rambit, you made the right decision not getting the TSB - if it ain't broke, don't "fix" it).

I've been looking through some of the information at 300cforums.com about the Predator, and may get one. This would probably be my last resort though. The thought of reprogramming factory settings using an aftermarket tuner is a little bit scary to me. I don't like tinkering with stuff anymore, and learned many a lesson (including some expensive ones) modding a Mustang Cobra several years ago. I've read lots of posts about different programmers used on different vehicles with different mods and it is all a little bit confusing. Some people have had problems with different programmers, while others have not. For the most part, It sounds like people have been happy with the Predator, but I'm a bit scared to do anthing like that yet.

I just don't understand how the SRT engineers could create transmission programming with such a major problem, if this problem is in fact widespread, can't be repaired by the dealer, and is not limited to just my car. The original programming was causing some (again, the consistency problem) SRT8s to bump the rev limiter, which in my opinion is an unacceptable problem in a high-performance car. Then the engineers came out with a TSB that seems to resolve that shift hesitation problem on the older models, but their solution takes away the ability to hold gears at redline. Although it isn't the optimal solution, I could live with it not holding the gear IF it shifted at redline as they advertise. I would rather be able to control it myself than have it shift prematurely for me.

Maybe I will try pulling fuse #2 as some have suggested helps for the 2008 models. I wonder if I would have to pull the fuse on a regular basis, like everytime I'm caught in traffic and can't drive it the way it was meant to be driven. It would be very inconvenient to have to pull the fuse every day.

Oh well...I will go to the dealer and see if there is anything they can do. If they can't fix it, maybe I'll try using the Predator or pulling the fuse.

Thanks for listening.

Edit: Dumb question: Can fuse 2 just be removed permanently or does it need to be pulled and then put back before I can drive? I guess I have more research to do, but I'm lazy. ha haa!
 

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Yeah Ken, these cars learn fast and can adapt to a more economy minded mode, which includes shifting BTW. Pulling fuse 2 in your case for 15 seconds clears the adaptive memory. What you have to do right after that is drive with "spirit" afterwards. The problem is it starts relearning all over again, so whenever you feel it's going back to the granny mode just pull it again.

I also think if you did this as soon as possible you're probably going to notice a big difference from what you're experiencing now.

EDIT: Just saw YOUR edit...haha. No, you gotta put it back!!!

Bernie
 

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I will let you know, from my experience, mine shifts right before redline and not a rpm sooner... I'm on an 08 with the old SRT8 logo on the seats, got the car in December and it was manufactured in October. Just FYI
 

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Going to the dealer will only frustrate you more - don't waste your time. You know a lot more about the car then they do. Plus, there is no tranny TSB for the '08s, it's only for 05s and 06s. The 07s and 08s came with that revised programming. Pulling the fuse every few days to a week should give you a noticeable improvement.

Supposedly the Predator can give you the option to hold the gear in autostick again, I just got mine yesterday so I haven't had a chance to play with it...I can tell you the car shifts and drives much better with the Predator/CMR tune than before. I also don't think you will find any mixed reviews on it, and I don't think it can be blamed for any problems on a stock car, only the guys with heads/cam upgrades were having problems before the CMR tuning.

Trust me, if you had an '06, you would definitely want the flash that all of us who drive our cars hard now have. I can't think of anyone who hasn't done it...it's that much better. The Predator, seems to make it that much better again.

Eric
 

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Great Shifts

My '06 used to shift early sometimes too. No, I never got the "Death Flash" from the dealer, surrendering my ability to hold gears for friggin ever if I choose to.

I added the GSM TCM which raises the line pressure and ALL of my shifts became harder and more consistent.

Then I added the Diablo Predator with the raised shift points and my car lurches forward when shifting gears at WOT and gives a little neck snap. Now it shifts just the way I always thought it should have.

I understand that you would like to update your '08 without going the predator route, but if you drive my car, or anyone elses that shifts right, you'll see just how worth it these mods are!!!

Good Luck,
 

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srt8man

There is absolutely nothing wrong with your transmission. It is performing exactly the way it is supposed to. And your car is not really upshifting at 5500 rpm's at WOT. Rambit was correct when he said that the tach lags in 1st gear (because the needle can't keep up with the actual rpms.) What you think is a shift at 5500 rpms is more than likely happening just before 6100 rpms.

There is a little trick you can do to verify this. Go into the EVIC diagnostic mode by holding down the music note & compass buttons simultaneously for roughly 10 seconds until the diagnostic screen appears. Use the up/down buttons to scroll to the screen that shows your MPH & RPMs. Then put your car in auto-stick where you have some room for a WOT run. Watch the digital RPM's closely and you will notice that the car is actually shifting over 6000 rpm's. I know it's difficult to drive and watch the EVIC at the same time and concentrate on the shift point, so it wouldn't hurt to have a passenger with you. You will be surprised to find out that your car actually shifts at a much higher RPM than you thought.

DanRealtor brings up a good point about the Predator. IMO, the best feature of the Predator is the MUCH improved shifting that you get. It will actually launch you forward on the shifts during WOT, like a kick in the seat. I've actually chirped my tires on the 1-2 shift in 85 degree weather. You don't need the GSM TCM. The Predator does this goodness all by itself. The Predator will make your car perform the way it should have performed right from the factory, like the beast that it is. Now go out and get yourself one. Also be sure to pick up an AFE-2 CAI for even more power coupled with the Predator. Tbyrne has a package deal going for the 2 units for $499.
 

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Tbyrne has a package deal going for the 2 units for $499.
Now that is a good deal, I heard he took a little time off though. Anyone verify? I paid $600 for the same setup over separate transactions and thought I did allright.

Eric
 

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Discussion Starter #16 (Edited)
I will let you know, from my experience, mine shifts right before redline and not a rpm sooner... I'm on an 08 with the old SRT8 logo on the seats, got the car in December and it was manufactured in October. Just FYI
Thanks for letting me know about your experience. The build date of my car was 10/22/07 and I picked mine up the day before Thanksgiving, so our cars were built around the same time.

Going to the dealer will only frustrate you more - don't waste your time. You know a lot more about the car then they do. Plus, there is no tranny TSB for the '08s, it's only for 05s and 06s. The 07s and 08s came with that revised programming. Pulling the fuse every few days to a week should give you a noticeable improvement.

Supposedly the Predator can give you the option to hold the gear in autostick again, I just got mine yesterday so I haven't had a chance to play with it...I can tell you the car shifts and drives much better with the Predator/CMR tune than before. I also don't think you will find any mixed reviews on it, and I don't think it can be blamed for any problems on a stock car, only the guys with heads/cam upgrades were having problems before the CMR tuning.

Trust me, if you had an '06, you would definitely want the flash that all of us who drive our cars hard now have. I can't think of anyone who hasn't done it...it's that much better. The Predator, seems to make it that much better again.
Eric
You are probably right about the dealer not being able to do anything, but the next time I'm there I will ask anyway. It couldn't hurt. I will try pulling the fuse and see if that helps, but I doubt it will help because I can drive it around like a maniac for quite some time and it still seems to do the 1-2 upshift prematurely. I will look into the Predator. From what you and others have said it really sounds like I can't go wrong with it. I just don't like tinkering with stuff. I just want to put gas in and go. ha haa!

My '06 used to shift early sometimes too. No, I never got the "Death Flash" from the dealer, surrendering my ability to hold gears for friggin ever if I choose to.
I added the GSM TCM which raises the line pressure and ALL of my shifts became harder and more consistent.

Then I added the Diablo Predator with the raised shift points and my car lurches forward when shifting gears at WOT and gives a little neck snap. Now it shifts just the way I always thought it should have.

I understand that you would like to update your '08 without going the predator route, but if you drive my car, or anyone elses that shifts right, you'll see just how worth it these mods are!!!

Good Luck,
I'm with you and Rambit about the TSB flash from the dealer. If the car doesn't bump the revlimiter and have shift hesitation, I would just leave it alone and retain the ability to shift myself (something I wish I could do given my current situation). It sounds like you are with all the others about Predator. I may go that route when I get some spare cash.

srt8man
There is absolutely nothing wrong with your transmission. It is performing exactly the way it is supposed to. And your car is not really upshifting at 5500 rpm's at WOT. Rambit was correct when he said that the tach lags in 1st gear (because the needle can't keep up with the actual rpms.) What you think is a shift at 5500 rpms is more than likely happening just before 6100 rpms.
There is a little trick you can do to verify this. Go into the EVIC diagnostic mode by holding down the music note & compass buttons simultaneously for roughly 10 seconds until the diagnostic screen appears. Use the up/down buttons to scroll to the screen that shows your MPH & RPMs. Then put your car in auto-stick where you have some room for a WOT run. Watch the digital RPM's closely and you will notice that the car is actually shifting over 6000 rpm's. I know it's difficult to drive and watch the EVIC at the same time and concentrate on the shift point, so it wouldn't hurt to have a passenger with you. You will be surprised to find out that your car actually shifts at a much higher RPM than you thought.

DanRealtor brings up a good point about the Predator. IMO, the best feature of the Predator is the MUCH improved shifting that you get. It will actually launch you forward on the shifts during WOT, like a kick in the seat. I've actually chirped my tires on the 1-2 shift in 85 degree weather. You don't need the GSM TCM. The Predator does this goodness all by itself. The Predator will make your car perform the way it should have performed right from the factory, like the beast that it is. Now go out and get yourself one. Also be sure to pick up an AFE-2 CAI for even more power coupled with the Predator. Tbyrne has a package deal going for the 2 units for $499.
Thanks for the tip about using the digital tach to compare to the analog one. I will definitely give that a try when I get a chance and report back my results. I suppose it's possible that the analog tach is lagging behind the actual RPMs, but on some runs it feels and sounds different around the time it shifts. Plus, on some back-to-back 0-60 runs (I've done many) where it feels like it's short shifting, my times are off by a couple of tenths from the runs where it seems to shift right. I know some say that the 0-60 EVIC timers are not that accurate, but I think it does give a good relative comparison. On the runs where it seems to be shifting properly, the EVIC typically shows 0-60 in the 4.5-4.6 second range, and I did manage to pull off a best of 4.44. On the runs where it feels like it's short shifting, the EVIC typically shows 4.7-4.9 for my 0-60 time. Not bad for a completely stock SRT8, but not as consistent as I would expect for an automatic. Sometimes, depending on the road surface, I hear a bark from the tires on the 1-2 upshift. Shifts are always firm, but of course I would like them firmer so I will definitely consider the Predator!

Edit: One thing I would like to point out is that once I'm rolling along at highway speeds the transmission works flawlessly. It downshifts with such ferocity in the 40 mph range and at highway speeds that sometimes it feels like it's going to spin the tires.
 

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Sort of

I sort of agree with DaveW68. Yes, your tranny probably is functioning as DCX intended it to. Yes, you don't NEED the aftermarket TCM but it does make a significant difference on the WOT shifts. I have driven with the Diablo & stock TCM: Noticeable difference. My car shifts firmly, but civilized at part throttle. It shifts like a muscle car at WOT, breaking the back tires loose (if I want) on the 1-2 shift and chirping 3rd gear. The raised line pressure from the GSM TCM does make a difference. Of course you don't NEED it, but it sure is fun to have!!!!

Cervical collar not included!
 

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another "spin"

Ken,

Do you have RSA tires or F1's?

My car when new came with RSA's and only occasionally exhibited the behavior you are experiencing, so I chose not to update it.

But you should note that if you are experiencing wheelspin (even just a little)at the top of first the feeling can be exactly as you've described.

Now, with better biting rubber I no longer even get the occasional "blip".

Note that the predator is plug and play, so simple even I could do it!
 

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Discussion Starter #19
My car has the RSAs. I'm going to try a couple of different things. I'm going to use "diagnostic" mode to monitor the digital RPMs and compare to the analog tach. All of my tests so far have been at WOT, and it really doesn't feel or sound like there is any wheelspin. I'm going to also try bringing the revs up slowly to redline while watching both the analog and digital tachs to see when it shifts. If I do it slowly, it should definitely hold 1st grear until the tachs reach redline.

By the way, when my RSAs are worn out, I will probably be replacing them with Toyo Proxes (275s rear, 245s front) for better traction. I also am told they last longer than the RSAs. After the new tires, I will look at getting the Predator. Everyone here seems to have lots of praise for it.

Thanks for your advice.

Ken

Ken,

Do you have RSA tires or F1's?

My car when new came with RSA's and only occasionally exhibited the behavior you are experiencing, so I chose not to update it.

But you should note that if you are experiencing wheelspin (even just a little)at the top of first the feeling can be exactly as you've described.

Now, with better biting rubber I no longer even get the occasional "blip".

Note that the predator is plug and play, so simple even I could do it!
 

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Also be sure to pick up an AFE-2 CAI for even more power coupled with the Predator. Tbyrne has a package deal going for the 2 units for $499.
Please note that although TByrne Motorsports is still listed as a supporting vendor, the company has been out of business for quite some time.

bruno
 
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