[Malibu Red]

I've had my 2009 LT Malibu (2.4L/6-speed) for ~ 4 months. I have over 8k miles on it.

This car shifts hard in slow traffic. I've grown to dread the shift shock while starting to accelerate from a slow coast. It feels like the car doesn't know whether it should start in 1st gear or 2nd. Under normal accerlation from a start the shift shock seems ok (not great but acceptable).

I was hoping that the transmission would "break-in" but it doesn't seem to be getting better.

Is anyone else experiencing this?

 

[samwilson66]

Even I am facing the same problem can any body help me?

 

[catfang]

yes you are not alone. Check here for someone who complained and did a "TCM" flash. I think they cleared the transmission module or something..not sure. I'm mentioning this to the dealer on my next visit.

 

[Dash8-300]

I will do the same cause mine is so bad if my coffee didn't have a lid; I'd be wearing my cup of coffee.

 

[Malibu Red]

Last weekend I took the care into the dealership for the TCM flash. The shift shock has been reduced.

I believe the new TCM flash change tells the trans to be in 3rd gear while in slow (<15 mph) stop and go traffic. It doesn't seem to hard shift between 1st and 2nd gear now.

Down side:
Since the flash, I've notice that when first starting the car in the morning (car is cold), the transmission revs up to 3000 RPM's in first gear when driving. After the first shift there is no problem.

Basically when I leave the garage and drive to the first stop sign the car revs up to 3k without shifting! It's happened every morning since getting the flash update.

Grrrr....

 

[cldouglass]

I don't believe this issue is totally isolated to the 2.4 with the six speed. I also have the same kind of issue with my 08 LTZ with the six speed transmission and it does almost the same thing. Normally notice it when I let off of the gas and coast for a bit, usually when approaching another car from behind. After talking to the service rep from my now longer local service department (since GM closed the one dealership in town), she says the problem is due to the cars computer thinking that everytime you let your foot off of the gas or even coast sometimes for short periods, the computer is predicting that you are going to slow or stop. This causes the cars transmission to delay shifting and the car's computer to also delay getting back into the throttle, thus the sudden jerk when everything catches up. Kind of makes sense but either way mine is going into the service department here next week for another small issue and I am going to have them check it then. I will keep you posted when I get some feedback.

 

[Dash8-300]

Took mine (08 2lt V6) in to get a brake service and spoke to the tech about the hard shifting and mentioned a flash/update. As you might have predicted he responded by saying there's no update or flash because there are no recalls on the car. I remember reading on here a TSB # of some sort that had to do with this problem. I'll do a search and next time I'll have that in hand when I go.

 

[dmw2692004]

i have the same problem with my 08 LTZ, I also get hard shifting sometimes at high revs.

 

[texasrox]

There is another thread covering this issue, which may provide some additional information.

My 2.4 6-spd had the same issue, found out about the 'TCM' update here on this site. I took my car in and asked the service advisor to have the TCM flashed. He first said no updates were available for this car, I asked him to verify that there were no updates. My advisor later called stating that they were having to download the updates from GM, they weren't initially in the dealers computer.

The end result is that the update has reduced my cars problem by about 98%, every once in a great while a jerky shift gets through when in traffic.

 

[Duckybill]

There is another thread covering this issue, which may provide some additional information.

My 2.4 6-spd had the same issue, found out about the 'TCM' update here on this site. I took my car in and asked the service advisor to have the TCM flashed. He first said no updates were available for this car, I asked him to verify that there were no updates. My advisor later called stating that they were having to download the updates from GM, they weren't initially in the dealers computer.

The end result is that the update has reduced my cars problem by about 98%, every once in a great while a jerky shift gets through when in traffic.

I purchased a 2010 LTZ 4 cyl, 6 speed 2 months ago. Where can I find this TCM flash info?

 

[Silver LTZ]

I purchased a 2010 LTZ 4 cyl, 6 speed 2 months ago. Where can I find this TCM flash info?

http://www.chevymalibuforum.com/forums/showthread.php?p=26742#post26742

Post 114.

 

[Duckybill]

http://www.chevymalibuforum.com/forums/showthread.php?p=26742#post26742

Post 114.

That was fast. Thanks!

 

[Duckybill]

Should I assume that this update is for my VERY new 2010 LTZ? I do notice some shifting problems.

 

[Silver LTZ]

Should I assume that this update is for my VERY new 2010 LTZ? I do notice some shifting problems.

You would think the new ones would have the updated software. But that car might have been sitting around a while. The new updates are very new....

 

[JWW]

I don't have this hard shifting problem, but I do experience the tranny down-shifting into 1st gear when I slow-roll a 'stop'. The action isn't nearly as smooth as it should be, the computer should have been programmed to go to 2nd in this instance. I've found a cure though!

When I'm slow-rolling a stop (yes, I know it's illegal) and I don't want the tranny to down-shift to 1st, I've found that in the last 30 feet of the slow-down, I brake with my left foot and then barely press down on the accelerator with my right foot. I then let off the brake and slowly accelerate away, the tranny stays in 3rd gear for a nice smooth get-away.

 

[Silver LTZ]

I don't have this hard shifting problem, but I do experience the tranny down-shifting into 1st gear when I slow-roll a 'stop'. The action isn't nearly as smooth as it should be, the computer should have been programmed to go to 2nd in this instance. I've found a cure though!

When I'm slow-rolling a stop (yes, I know it's illegal) and I don't want the tranny to down-shift to 1st, I've found that in the last 30 feet of the slow-down, I brake with my left foot and then barely press down on the accelerator with my right foot. I then let off the brake and slowly accelerate away, the tranny stays in 3rd gear for a nice smooth get-away.

I wouldn't wanna deal with having to do that though. I think I might try this "reflash".

 

[E_Net_Rider]

I wouldn't wanna deal with having to do that though. I think I might try this "reflash".

I totally agree with not doing that. Sounds like an accident or damage about to happen.

It would be nice to have some way of knowing what each of our vehicles has for firmware. Very hard to compare situations without knowing what we have.
I too experienced some of the quirky, slightly hard shifts, downshifts, at first. I can not say if dealer did update when I took it in for other issue.

That is, maybe that is part of the reason for change, or maybe it is learning my driving or maybe I'm learning its programming and handling it differently.

I do tend to drive like I have the egg on the accelerator and I don't want it to fall away if I let off it too quickly. Of course there are those times you must brake. I try my best to anticipate lights. When approaching a red one I ease off the throttle way ahead of time. I even try to adjust speed so that I will be rolling at the maxiumum possible speed when the light changes and traffic is rolling again. I will even brake to a slower speed so that I coast or drive into the traffic pattern when it is moving again.
I found this technique added 2 to 3 MPG to what would otherwise be 16 or 17 MPG on Premium fuel. But then there are those times that traffic is like jam. Thick and slow to move, and you just have to live with it.

 

[Duckybill]

Had my A6, 4 cyl, 2010 LTZ reflashed several weeks and 2000 miles ago. It is as bad or worse than ever when driving under 30. I got stuck in a traffic jam for half an hour on icy road. The shifting was AWFUL! I haven't had time to take it back yet. Not happy!

 

[E_Net_Rider]

I don't have this hard shifting problem, but I do experience the tranny down-shifting into 1st gear when I slow-roll a 'stop'. The action isn't nearly as smooth as it should be, the computer should have been programmed to go to 2nd in this instance. I've found a cure though!

When I'm slow-rolling a stop (yes, I know it's illegal) and I don't want the tranny to down-shift to 1st, I've found that in the last 30 feet of the slow-down, I brake with my left foot and then barely press down on the accelerator with my right foot. I then let off the brake and slowly accelerate away, the tranny stays in 3rd gear for a nice smooth get-away.

I don't know anything of the hard shifts, but it seems that engine braking is actuated when the accelerator is fully released. There may be some modifiers to that condition.
Similarly when resuming cruise. That is if I'm bringing the vehicle up to speed with accelerator it often does not accelerate harder than my foot, but if I let off the pedal at some point after engaging, it might then drop a gear and accelerate harder.
It seems the vehicle is trying to take control toward proper driving habits. That is start decelerating long before getting to that red light, ideally it changing to green before you get to it and adjusting speed so that you arrive at it with maximum possible speed, not time. That is brake if necessary when you first notice the condition to a speed that should have you merging with the traffic as it gets up to speed.
Next thing you know we'll be driving those fully automated vehicles mentioned 40 years ago and they might be called a more recent reference, "Johny Cabs".

 

[bf1942]

Last weekend I took the care into the dealership for the TCM flash. The shift shock has been reduced.

I believe the new TCM flash change tells the trans to be in 3rd gear while in slow (<15 mph) stop and go traffic. It doesn't seem to hard shift between 1st and 2nd gear now.

Down side:
Since the flash, I've notice that when first starting the car in the morning (car is cold), the transmission revs up to 3000 RPM's in first gear when driving. After the first shift there is no problem.

Basically when I leave the garage and drive to the first stop sign the car revs up to 3k without shifting! It's happened every morning since getting the flash update.

Grrrr....

Since I drove my 08 2Lt 2.4L 4 speed of the lot that cold snowy Dec 2008

The first thing I noticed when accelerating up an on ramp was how long the 1st gear stayed engaged, it was up around 3000 Rpm + before the shift.

Still today 5,000 miles later every morning she revs way up to 3000 Rpm +
durng the first real acceleration.
After that it shifts much sooner, but is pretty hard shifting when I am lugging the engine, or accelerating slowly.

The shifts going up seem much smoother when I am feeding it more gas.

It has started to shudder shift a little the last couple of weeks, when I have my foot off the gas and need to stop quickly and am going downhill?

weird, but not as bad as some mentioned here , with the coffe lid statement.