[Piggy]

Having a problem with my 09 2LT with the ecotec. I have just over 6000 miles on it. Sometime around the 3000 mile mark I noticed an occasional shudder coming from the front of the car when accelerating through 12-20 mph. I can also sense something out of balance at around the 60mph and up mark but this is minor in comparison to the low speed shudder. This has now grown into a very annoying intermittent problem as I spend a lot of time on the hwy in stop and go traffic and at high speeds.

It does not seem to happen when the car is cold. Sometimes takes 15 min to 30 min to show up. It comes in varying degrees of severity. At its worst there is a very noticeable 6 or 7 pulses or shudders which can be felt in the steering wheel and through the seats of the car.

If I keep it in 1st or 2nd via manual mode it still happens. When in Auto the transmission functions smoothly through it.

The engine is not running rough, it powers smoothly through the shudder with no noticeable rpm dips peaks. However it does seem more frequent and stronger when the engine is under load like going up a hill or starting with the wheels turned.

I have had it at the dealer for this problem. They drove it and say they don’t notice anything wrong. I suspect they ignored my "it doesnt happen when the car is cold". They balanced the wheels with no effect.

Everyone who has spent significant time in the car with me asks what is wrong with it, so I know I am not crazy!

I am taking it back to the dealer but wondering if anyone else had any luck squashing this bug? Motor mount problem maybe?

 

[Macleod52]

I don't know if this is the same as your situation, but I had something similar happen last night. I was accelerating up to speed (30mph) not more than 2500rpms and the car felt like it was surging, or lunging. It happened sporatically last night and last night only. It's almost as if the computer had a hiccup.

Another way to describe it is if you're driving a stick shift and you've got it in too high of gear trying to take off (not giving it enough gas). It was like that but not nearly as violent. Definitely strange.

 

[bballr4567]

Id take it to the dealer and drive the car with them in it. Thats the only way for the tech to know exactly what you are talking about and feel it for themselves.


Our car does something similar but it only does it cold and when it shifts from 1-2 while accelerating the car just falls flat out its face and shudders a tiny bit. Once warmed up it doesnt happen so Im not worried about it as its probably just the transmission fluid not being up to driving temp.

 

[Piggy]

Hi guys thanks for your responses. There is no loss or surge of power with my car, just the shaking.

 

[Silver LTZ]

Do you have the A6? If so it might be the typical transmission related shudders. Alot of the A6's have it. There are some reflashes the dealership can do, I just had them done. It did help, but not eliminate it. Mines more so at 45-60 that I notice it a little. Some days it is there, others it's not.

 

[Piggy]

It is the Ecotec 4.

 

[slls]

Do you have a 6 speed transmission?

 

[Silver LTZ]

It is the Ecotec 4.

I know, but do you the A4 or A6 transmission?

 

[E_Net_Rider]

Similar experience, that is shudder at low speeds. Vaque to the point I have no ideas, yet.

 

[alphagtp]

the same happens to mine, when is on 2nd gear and at low rpm's it does that until it either gains speed or shifts down to first, I just figure it was normal for a 4 cyl on a heavy car as is not that bad, I don't know, may be somebody will know how to fix this?

 

[E_Net_Rider]

the same happens to mine, when is on 2nd gear and at low rpm's it does that until it either gains speed or shifts down to first, I just figure it was normal for a 4 cyl on a heavy car as is not that bad, I don't know, may be somebody will know how to fix this?

Is it possibly at the 2-3 shift?
New experience yesterday. Temperatures cooler than usual and cold tranny was very sluggish on 2-3 shift. So slow that it felt like it went into neutral. Observing tach, the RPM dropped more slowly than other shifts and stopped its swing about half way through the expected RPM drop and then after some hesitation it dropped rapidly to the expected positive engagement RPM. Very much like tranny was slipping for some time before fully engaging that clutch.

What would be useful in diagnosing is the exact shift sequence and expected speed/RPM range.
Shift sequence being the point that convertor lock occurs along with what clutches are engaged. That is there is not a single clutch for each gear.
Think of it as a set of binary switches. Clutch 1 for low gear. Maybe 1&2 for second gear. 3 for 3rd, 3&1 for 4th, and so on. One clutch will be dedicated for reverse, and the TCC is mechanically separate from the gearing in the tranny body.

If I see a pattern developing, I will run it by a tranny shop that has the hand held computer and can read it while driving. If it is a shift problem they will know it.

 

[Piggy]

Mines a 6 speed...thought all 2LT 2009 were?

 

[Silver LTZ]

Well if the OP's car is a A6, I bet what your feeling is the typical tranny "shudder" I mentioned before. Try getting the updates at the dealer, might help a little. Like I said, on my car the updates helped, but did not eliminate the shudder. But I am super sensitive to it now, most passengers can't even notice when I ask them to try to feel it. I seem to feel it the most in the throttle pedal it seems....


I plan on buying aftermarket pedal covers and putting rubber in between the pedal and the covers to help isolate the vibrations....I read that some guys do this on the G6 boards. I just wish they spent a little more R&D on the torque converter design of the A6.

 

[E_Net_Rider]

Mines a 6 speed...thought all 2LT 2009 were?

It would seem not. Lots of BU at the dealer when I shopped, but it seemed that mine was the only one with A6 other than a couple of LTZ they had. I said leather was a must which eliminated most they had.

 

[E_Net_Rider]

Well if the OP's car is a A6, I bet what your feeling is the typical tranny "shudder" I mentioned before. Try getting the updates at the dealer, might help a little. Like I said, on my car the updates helped, but did not eliminate the shudder. But I am super sensitive to it now, most passengers can't even notice when I ask them to try to feel it. I seem to feel it the most in the throttle pedal it seems....


I plan on buying aftermarket pedal covers and putting rubber in between the pedal and the covers to help isolate the vibrations....I read that some guys do this on the G6 boards. I just wish they spent a little more R&D on the torque converter design of the A6.

Why the torque converter?

 

[Silver LTZ]

Why the torque converter?

It's the lockup/how it locks up of the torque converter that is believed to
cause the vibrations/shudders. Plus the tranny seems to upshift too soon sometimes and not downshift from 6th when it should. IMO the tranny is programmed to much towards economy which effects driveabilty.

 

[dabeertender]

I have an 08 ecotec with the 4sp....I notice similar symptoms, I stress similar not identical. I actually get vibration at times through the steering wheel as well. And the car is a dog when you accelerate from a dead stop, no low end balls....I guess I should have bought a vette for that though...

 

[E_Net_Rider]

It's the lockup/how it locks up of the torque converter that is believed to
cause the vibrations/shudders. Plus the tranny seems to upshift too soon sometimes and not downshift from 6th when it should. IMO the tranny is programmed to much towards economy which effects driveabilty.

I'm not familiar with the last few years of programming. You used to be able to count on engagement of TCC or overdrive at certain speeds for a particular model. Some had TCC first, others went into OD before TCC lock.

With 6 speeds it would seem reasonable for TCC to engage at steady speeds other than high gear, maybe the top three even, just to reduce the heat produced by the convertor when it is unlocked. And it would probably unlock during upshifts.

Right now my main concern is over the feeling of total disengagement going into 3rd when it is cold.