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Discussion Starter #1
When our Terrain was in the shop due to the power steering debacle the other TSB's that were out at the time were remedied, including the ECM Reprogramming. From what I've read on this forum, this has something to do with the transmission?

In any case; in the couple of weeks that we've had the vehicle back, we've noticed 2 problems that has been getting progressively worse. When attempting to move forward from a stop, occasionally the vehicle does not seem to respond for a short period of time. It almost feels like the parking brake is stuck on, but we never use the parking brake and I've checked it, it is not stuck. After a few seconds everything seems to return to normal, except for the second problem.

The second problem appears when trying to accelerate in a moderate to hard fashion, say when turning onto a highway, going from low speed to highway speed quickly. Before the Terrain went into the shop, the vehicle would accelerate and shift smoothly, usually hitting 5500-6000 RPM before shifting to the next gear (50-70% throttle).

Now, with the same throttle input, it will stay in the same gear until it nearly redlines, then it will blip (shifts up, down, then up again). It's kind of jerky, and feels like you're driving the piss out of it even when you really aren't. My parents were down to visit yesterday, and before they came down they were test driving an Equinox with the V6 as well, and even they noticed it. So it's not just me.

Anyways, has anyone else noticed any differences after the ECM updated?

Just to sum up, these problems only appeared after the ECM update. We will be booking it in to be checked out by the dealership, but we're frustrated with the service head there right now, so we've been putting it off.
 

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Discussion Starter #2
Well, we will take it in and see what happens. We've thought about opening a file with GM, but are afraid of pissing the dealership off. Especially in a small town, everybody is connected one way or another.
 

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Mobius said:
Well, we will take it in and see what happens. We've thought about opening a file with GM, but are afraid of pissing the dealership off. Especially in a small town, everybody is connected one way or another.

SnowItch said:
I hear you. I've lived in small towns - definitely changes the dynamics.
It is a tough situation, but be assertive, not aggressive.
You paid good money for what should be a top notch product.
The service should be exceptional as well.
GM shut down a lot of dealerships.
Your local dealer should be jumping through hoops to keep you happy, you shouldn't be worried about kicking up a little dust, IMHO.
 

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We had actually heard about this issue before buying our 'Nox. We made sure the dealer had already applied any known ECM updates to the vehicle before the purchase. We've never seen any problems with it in this regard.
 

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Discussion Starter #5
SnowItch said:
Your problem sounds like an issue that someone reported on GMInsiders with a 4. An engineer actually traveled down to ride with him, experienced the issue, and flashed his ESM right there, and it took care of the issue.
Snowitch, do you have a link to that particular thread?
 

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Discussion Starter #6
Thanks for the quick reply, that saved me a lot of searching.

It looks to be a separate problem though, not related to what we're experiencing. We have a booking for Wednesday, and my fiancee had mentioned that I had read that there might have been a similar problem that was fixed with a reflash. They wanted to see that information, if it was indeed a similar problem. Unfortunately it wasn't, hopefully we can get this fixed up on Wednesday.
 

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Discussion Starter #7
So the dealer checked it over and went for a road test, and I quote, "the road test seems normal for the new six speed transmissions." They reflashed the ECM, but it was current and updated, no change. The tech also said that the throttle lag is normal for the V6.

I'm not sure I agree with either statement, but I guess we'll have to wait and see if anyone else has a similar issue.

Maybe we're just nit picking, but who knows.
 

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Mobius said:
So the dealer checked it over and went for a road test, and I quote, "the road test seems normal for the new six speed transmissions[/color]." They reflashed the ECM, but it was current and updated, no change. The tech also said that the throttle lag is normal for the V6.

I'm not sure I agree with either statement, but I guess we'll have to wait and see if anyone else has a similar issue.
You're kidding right?
You mean to say the tranny blipped up to redline and the Tech considered this normal?
You mentioned this fact to the Tech before he (she) took it for a drive?
(I had to delete part of your posts in the quote due to the "jumping screen" issue with IE8 and the Simple LLC software, just FYI).

Mobius said:
until it nearly redlines, then it will blip (shifts up, down, then up again)[/color]. It's kind of jerky, and feels like you're driving the piss out of it even when you really aren't.
 

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Mobius said:
The second problem appears when trying to accelerate in a moderate to hard fashion, say when turning onto a highway, going from low speed to highway speed quickly. Before the Terrain went into the shop, the vehicle would accelerate and shift smoothly, usually hitting 5500-6000 RPM before shifting to the next gear (50-70% throttle).

Now, with the same throttle input, it will stay in the same gear until it nearly redlines, then it will blip (shifts up, down, then up again). It's kind of jerky, and feels like you're driving the piss out of it even when you really aren't. My parents were down to visit yesterday, and before they came down they were test driving an Equinox with the V6 as well, and even they noticed it. So it's not just me.
I wonder if this is related to a TSB that was put out about the front springs???? Anyone want to dig that TSB up????
 

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In regards to the lag in acceleration preceded by high rpms, I experienced that on several different makes and models of vehicles when doing test drives recently. It was an ex-mechanic turned sales guy who finally told me to disengage the traction control and see the difference--much more timely response. So perhaps you are used to the more direct response of a vehicle with either no traction control or differently tuned traction control? Try your vehicle for a drive with the traction control and eco mode both off and see if you notice a difference in response. All the programming and logic added in to keep us 'safe' and using less gas sometimes just gets in the way...

By the way, my wife's 2004 SRX and my 2000 Corvette both have stability/traction control and they both respond without the rpm windup/lag...but they are both V8's :)
 

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Discussion Starter #11
This is the first vehicle that we have had with traction control, DSC etc. However, it is not the first vehicle I've driven with such, and have never encountered this problem before. I will give it a try though.
 

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We are up to about 5800 miles and maybe a half dozen times I have had the tranny do a hard shift into 3rd or 4th gear. This seems to happen under light to moderate acceleration. Doesnt happen often enough to be able to pay attention to when it happens. Its obvious enough when it happens that my wife says "what was that" Maybe someone can tell me so I can tell her. Thanks.
 

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TerryG said:
We are up to about 5800 miles and maybe a half dozen times I have had the tranny do a hard shift into 3rd or 4th gear. This seems to happen under light to moderate acceleration. Doesnt happen often enough to be able to pay attention to when it happens. Its obvious enough when it happens that my wife says "what was that" Maybe someone can tell me so I can tell her. Thanks.
Tell her, It was the tranny shifting hard.
 

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This sounds like a "if it an't broke, don't fix it" situation. If you had no issues with the way it shifted from the factory, then I would go to the dealership and insist that they flash back to the original firmware/software. (whichever it may be) The problem with firmware is that sometimes it doesn't allow a flash back to an older version...but there are ways around that in the computer/consumer electronics world so I would think this would be the same.
 

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I am so glad that I saw this post. I have had my 2011 for just under 2 weeks now, and twice when getting on the highway to go home from work, my transmission has been stuck in what I believe to be 5th gear when going 55, 60, 65 + mph, even though I had light throttle input - it definitely should have gone to overdrive / 6th gear. I am bring the car back today because it won't hold air in the front left tire either, always ending up at 5-7 psi lower than the other 3 (checked the pressure in the tire to make sure it wasn't the TPMS that was off... it was the tire). I traded my Infiniti FX35 in for this, which I had for 7 years without one issue, and this is a little scary after less than 2 weeks. Welcome back to American! At least they have good coffee and bagels at the dealership... I might be spending some time there!!
 

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TerrainKamchi said:
I am so glad that I saw this post. I have had my 2011 for just under 2 weeks now, and twice when getting on the highway to go home from work, my transmission has been stuck in what I believe to be 5th gear when going 55, 60, 65 + mph, even though I had light throttle input - it definitely should have gone to overdrive / 6th gear. I am bring the car back today because it won't hold air in the front left tire either, always ending up at 5-7 psi lower than the other 3 (checked the pressure in the tire to make sure it wasn't the TPMS that was off... it was the tire). I traded my Infiniti FX35 in for this, which I had for 7 years without one issue, and this is a little scary after less than 2 weeks. Welcome back to American! At least they have good coffee and bagels at the dealership... I might be spending some time there!!
My 2011 Nox has a similar issue, I have the 4 cy, and when I accelerate from 2nd-3rd gear or 3rd - 4th there is a lag...almost a bog in the motor, then jerks when it picks up. Its not a strong jerk, but enough for my wife to say "why did you pump the gas just now" I didn't honey :)

Its not too big of an issue now, but if it becomes more frequent and noticeable I'm going to take it in.
 

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Ok... so I went to my dealership the next day (they told me to bring it in immediately, and got it right in... they said they didn't want to send me away with a loaner, that they didn't want this to wait - of course, I haven't sent my survey in to GM yet ;), and they hooked it up to the internet, and a GM engineer called at the same time to do a scan of the electrical system, and look for computer codes, which there were none - that this is an electrically controlled transmission. Now, this situation happened on the same stretch of highway, under the same load, so it looks like a perfect combination of going up a slight grade, under mild / moderate acceleration caused the tranny to lock into gear, and eventually let go. I have since been on that same stretch twice, after they reflashed it, and it has not happened. Also, they took the small screw out of the corner of my tire, patched it, and the pressure is holding perfectly now! A few good notes: I have been getting 28+ mpg on the highway during break in, and will be going over to Amsoil 0W 30 soon with WIX filters, and a K&N air filter - let's see how that does. I also had a young lady in my car last night for the first time, and she LOVED it! Said the interior was beautiful, and loved the red lights glowing. Seems like GMC is heading down a great path... so if anyone from the mother company is reading this, please put blinkers in the side view mirrors for safety, install a push button start, instate a one touch button to raise at least the drivers side window, reduce the wheel well gap just a little bit / give some more ground clearance, and improve the stereo controls on the steering wheel (like being able to turn it on / off from there)... keep up the great work!
 

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Is that 28mpg u.s. if so then i dont get it. I only get 19 on firs fill up and im looking at 22 on my 2nd. I dont think ill ever hit 28mpg. 2011 nox 4cyl awd
 

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pacman said:
Is that 28mpg u.s. if so then i dont get it. I only get 19 on firs fill up and im looking at 22 on my 2nd. I dont think ill ever hit 28mpg. 2011 nox 4cyl awd
Just a friendly FYI...so your not waiting for his reply

That member was last on this Forum October 21, 2010, 07:29:26 AM
 

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I have recently had the sticking tranny issue on my Terrain. It happens in ECO mode. I turned it off and it didn't seem to have an issue. My tranny got stuck today in I think 3rd going from a dead stop at a light. It hung at about 3000-4000 rpm and wouldn't shift. I let off the gas to see if it would shift and then applied the gas, same RPM. Also, I have the shudder problem quite a bit, usually from a stop. I apply the gas and it has a slight lag then kicks in abruptly. Pretty jarring and annoying. I also had it where it wouldn't shift and almost redlined. I was accelerating to pass on the highway and I was at a slight grade and it just would not shift to the next gear. Really quite annoying and kinda worrisome. I am going to schedule an appointment with my dealership this week. It's a 2011 with about 3500k miles. The vehicle rides nice and seems pretty smooth most of the time, but this issue has come up too many times to ignore.
Has anyone come to a solution for this? Is it strictly computer or is it drivetrain?
 
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