# Light 'Bump' when Completely stopped



## TSURacing (Jan 1, 2011)

mainevent23 said:


> Hello!
> 
> I currently have about 4800 KM's on my Cruze LT Turbo w/ RS package. As far as I can remember, when I'm driving and I come to a complete stop, about 2 seconds later, I feel a faint 'bump', almost like someone is nudging me from behind (not the case). It varies from fant to very noticible. I took it into the dealer yesterday for the Recall and they said they had fixed it. I took it back out on the road today and I'm experiencing the same issue. So I called the dealer's service centre today and the guy put me on hold to talk to another person who works there that also owns the Cruze. He came back on the phone and said that the other gentleman experiences the same issue and its a known problem with the Cruze and to bring it by later for a test drive.
> 
> ...


Hey Adam
It is not a problem, it is a feature of the transmission. That bump you feel is the trans going into neutral at a stop to reduce drag on the engine and save fuel. You will also feel a similar slight nudge as it rengages when you begin to lift off the brake pedal. This is a common observance in Cruze owners but rest assured, it is there to help save you $$.

Please educate other owners and even the dealership personnel if you have to. Even some GM reps do not know about the feature apparently.


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## mainevent23 (Jun 8, 2011)

TSURacing said:


> Hey Adam
> It is not a problem, it is a feature of the transmission. That bump you feel is the trans going into neutral at a stop to reduce drag on the engine and save fuel. You will also feel a similar slight nudge as it rengages when you begin to lift off the brake pedal. This is a common observance in Cruze owners but rest assured, it is there to help save you $$.
> 
> Please educate other owners and even the dealership personnel if you have to. Even some GM reps do not know about the feature apparently.


Hi,

Thanks for your reply!

I took another Cruze LT Turbo around the sales lot and came to a complete stop at least 7 times and that car didn't have the same 'issue' I'm referring to. Even the service rep I was dealing with said his Cruze doesn't do this. Why would it be there on mine, and not another Cruze that had 4 Km's on it? :s I'm not questioning your answer at all, just wondering if its 'feature', why it wasn't on another car I tested? Even the demo I tested before buying it didn't have this.

Thanks again!


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## audog (Apr 28, 2011)

mainevent23 said:


> Hi,
> 
> Thanks for your reply!
> 
> ...


For what it is worth, my LTZ does not do this, 2K miles on it.


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## mainevent23 (Jun 8, 2011)

audog said:


> For what it is worth, my LTZ does not do this, 2K miles on it.


 
Really eh? I find it a little annoying. How about yourself? Do you just live with it?


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## SilverCruzer (Nov 30, 2010)

I have not noticed the bump, but when I first bought the car, I did notice it start to roll backwards after I removed my foot from the brake.
For some reason, it does not do this anymore. Did the "enhancement" go away? Did it get fixed/removed with one of the recall or TBS fixes?


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## audog (Apr 28, 2011)

mainevent23 said:


> Really eh? I find it a little annoying. How about yourself? Do you just live with it?


I don't notice any "bump" when I come to a stop in my car. Although I do notice a very slight engagement of the tranny when giving it gas from a stop sign, so I am assuming that the system to disconnect the transmission to save gas is working. But no "bump", I would have complained to the Service Dept if I did.


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## mainevent23 (Jun 8, 2011)

audog said:


> I don't notice any "bump" when I come to a stop in my car. Although I do notice a very slight engagement of the tranny when giving it gas from a stop sign, so I am assuming that the system to disconnect the transmission to save gas is working. But no "bump", I would have complained to the Service Dept if I did.


 
Sorry, I read your sentence wrong. lol

I did complain. So I guess I'll keep pushing it with GM's Customer Service.


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## mainevent23 (Jun 8, 2011)

SilverCruzer said:


> I have not noticed the bump, but when I first bought the car, I did notice it start to roll backwards after I removed my foot from the brake.
> For some reason, it does not do this anymore. Did the "enhancement" go away? Did it get fixed/removed with one of the recall or TBS fixes?


I took it in Monday for the recall. They found a fault in the tranmission, but I guess that was a seperate issue as the 'bump' is still there.


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## mainevent23 (Jun 8, 2011)

Out of curiousity, do you think this issue can be fixed without an error code? The service rep said it would be hard to determine the issue without one. But I'm just wondering if he's BS'ing me

Thanks


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## toydriver00 (May 4, 2011)

I get a bump also. It seems like it is coming from the front passanger side of the car.


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## audog (Apr 28, 2011)

mainevent23 said:


> Out of curiousity, do you think this issue can be fixed without an error code? The service rep said it would be hard to determine the issue without one. But I'm just wondering if he's BS'ing me
> 
> Thanks


I would think that there are a lot of issues with a car that won't generate an error code. Just because there is no error code, does not mean there isn't a problem. I believe he may be BS'ing you. It may be harder to determine the cause of a problem if the onboard computer doesn't tell you what area has an issue, but it's not impossible. People have successfully diagnosed car problems for a long time without error codes


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## mainevent23 (Jun 8, 2011)

toydriver00 said:


> I get a bump also. It seems like it is coming from the front passanger side of the car.


Mine feels more like it's on the drivers side, or just in general from the front of the car. :s Not sure what's going on. Have you taken it back to the dealer to complain?


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## mainevent23 (Jun 8, 2011)

audog said:


> I would think that there are a lot of issues with a car that won't generate an error code. Just because there is no error code, does not mean there isn't a problem. I believe he may be BS'ing you. It may be harder to determine the cause of a problem if the onboard computer doesn't tell you what area has an issue, but it's not impossible. People have successfully diagnosed car problems for a long time without error codes


Good to know, thanks!


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## cruzers (Dec 13, 2010)

mainevent23 said:


> Hi,
> 
> Thanks for your reply!
> 
> ...


TSURacing is correct, it's the transmission going into neutral when you come to a stop. The reason why the other cruze with 4 km didn't go into neutral is because it probably wasn't at full operating temp. Here's a section from the owners manual from page 9-26:

The vehicle has an automatic
neutral shift feature which allows
the transmission to automatically
shift to N (Neutral) when the vehicle
is stopped with a forward gear
engaged. The reduced load on
the engine improves vehicle fuel
economy.


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## Big Tom (Mar 8, 2011)

After my car has been parked, I get a lite "thump" from the rear after moving about 100-200 feet. It feels like something in the rear suspension.


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## scaredpoet (Nov 29, 2010)

mainevent23 said:


> Out of curiousity, do you think this issue can be fixed without an error code? The service rep said it would be hard to determine the issue without one. But I'm just wondering if he's BS'ing me


Well, I'm first going to say that I'm not so sure it's really a problem. I feel a very light bump too, and it's definitely something with the way the transmission is disengaging. It's not something that causes anyone discomfort though, and it doesn't affect the way the car rides or operates, so I just let it go. My last car, with a similar "fuzzy logic" transmission, misbehaved way worse than this from time to time, so for me this is nothing.

Other, newer-off-the-lot Cruzes might not do it - yet - because their transmissions haven't gone through as many miles and "learned" certain behaviors yet. And some may never bump like others. They're supposed to to adapt their operation based on a number of factors as the car gets driven, and that's what makes this hard to diagnose. It's not true that every Cruze transmission will behave *exactly* the same way. And that's the case for a LOT of modern transmissions n lots of cars now.

Don't like it? Blame Chrysler. They came up with the idea, and it stuck. Mainly because it works pretty well, most of the time.

BUT, by saying what he said, you service guy IS being pretty lazy, and expecting the car to diagnose problems for him when the fact is, the car can't diagnose _everything_. If the car's built in diagnostics were _that_ good, then he wouldn't have a job. 

Honestly, I would consider taking it to another dealer for service going forward. Maybe even have them look at the bump issue for you and see what they say.


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## mistereric (Aug 11, 2011)

SilverCruzer said:


> I have not noticed the bump, but when I first bought the car, I did notice it start to roll backwards after I removed my foot from the brake.
> For some reason, it does not do this anymore. Did the "enhancement" go away? Did it get fixed/removed with one of the recall or TBS fixes?


Jeez. So THATS why I was suddenly rolling backwards when stopped on a hill this afternoon, with light pressure on the brake pedal. Sounds like a good feature, until you unwittingly roll into the front of the poor schmuck behind you.


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## FanDamNCSU (Dec 23, 2010)

Big Tom said:


> After my car has been parked, I get a lite "thump" from the rear after moving about 100-200 feet. It feels like something in the rear suspension.


I feel like mine just started to do this with close to 11k on it. I don't seem to notice it all of the time but it feels/sounds like I just ran over something small. I can't reproduce the problem all of the time though, so I know if I take it to the dealer it will just be a waste of time. I plan on just driving it like normal and when I can reproduce the issue every time I will take mine in.


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## Gio93z (Sep 8, 2011)

normal feature of the transmission - my '11 LTZ does the same thing - slight roll back until it sees any wheel speed then it engages - and slight bump as you come to a stop - as stated, meant for fuel efficiency - there are reprograms for the TCM however that will probably not fix any 'bump' issues. also, yes it will take upto 250 miles before your TCM adapts to your driving style....upto 250 miles of driving AFTER a TCM/PCM reprogram also....each vehicle is slightly different and will react and act slightly different - i work at a Chevy dealer in North Jersey and unfortunatly, without any DTC's or poor driveability concers, it would be listed as 'no problem found and normal operation'.......agreed...it can totally get annoying! esp. if you have to stop and then gas it again quickly 5year/100k powertrain warranty =) don't worry


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## Jaycruze (Jul 11, 2011)

Big Tom said:


> After my car has been parked, I get a lite "thump" from the rear after moving about 100-200 feet. It feels like something in the rear suspension.


 
If I stop to get a coffee or get gas, Once I get back on the road the car jerks really hard into 4th gear every time and it only happens once, if i come to a stop and go again it doesn't happen again.

Is this what you are experiencing?


I took it to the dealer the other day and I tried to show him but I didn't let the car sit long enough before he tested it so it didn't happen. Then they changed the oil... of course after they change the oil and I go home it does it again lol... I'm a dumbass for not making them test drive it after the oil change.


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## cruze01 (Mar 25, 2011)

I started to notice this "BUMP" happening with my 2013 and took it in to the dealer along with a leaking water pump yesterday. I talked to them today and they told me that there is a service bulletin out on the problem and they have to replace the wave plate in the transmission. Apparently its a pretty big job, had to pull the trany and open her up....

If anyone else is experiencing this take it in. GM knows what and how to fix it now.


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## cruze01 (Mar 25, 2011)

Got my car back today, took them almost a week to fix it! Results are good and bad! Good= no more bump. Bad= transmission doesn't shift the same, can't say it isn't working rite just not the same. It used to shift sharp and fast, now it kind of rolls into the next gear, a little mushy feeling. Service ticket states diagnosis as "Variations in 1-2-3-4 clutch plates, replaced plates and seals as needed".


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## Robby (Mar 1, 2013)

The trans is 'adaptive'......it went to base programming while it was out of the car.
Takes, on the order of 500 miles to re-learn your driving habits so be patient.

Rob


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## mikeeitup (Aug 27, 2013)

This is why we don't buy automatics XD. Sorry I had to hehe
Mike


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## cruze01 (Mar 25, 2011)

Robby said:


> The trans is 'adaptive'......it went to base programming while it was out of the car.
> Takes, on the order of 500 miles to re-learn your driving habits so be patient.
> 
> Rob


Thanks for reminding me! You're rite, it got a little better today.


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