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I just got my new Traverse last week and I am already taking it to the service dept this Friday to get looked at so I wanted to see if anyone else has had this issue. If I have my car in reverse on even the slightest of inclines and take my foot off the gas it starts going forward and won't stop until I put my foot on the gas or break, kinda like a manual transmission would do. Likewise, in drive on a slight incline it will go backwards if I take my foot off the gas. Anyone have this happen? I'm hoping it's a software glitch in my downhill assistance or something but I really have no clue and the thought of transmission issues on a brand new car is freaking me out.
 

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that is 'normal' on the Lambdas.
many people have reported rolling back on hills- if they let go off the brake.

Ive read reasons for this--- the 6 speeds-- and the amount of line pressure in the trans..
But youre not the 1st to report this. Similar post on the Acadia, Enclave and I think Outlook forums.
I have not heard if theres a software patch for this.
But I doubt it.
I think many people got used to having the transmission HOLD the car on some uphills... (and or in reverse- then rolling forward)
 
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some have also said the size of the flywheel might have a play in this as well. I think we all have just gotten used to it
 

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The torque converters in modern cars are made to really get loose at idle, to help with fuel economy.

I was under the impression that the Traverses were supposed to have a braking system that held for a bit on inclines for starting. Part of the Stabilitrac system. Is this not true?
 

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no such system that im aware of.

theres something like descent control-- but thats when heading downhill- and you press on brakes- .

One member has posted about a feature that he thought held his Traverse on hills--- but i THINK... it was no valid.
 

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Some vehiles have "Hill Assist". The Traverse does NOT. Hill Assist will hold you brakes up to 2 seconds after you release the brake pedal, or when the accelerator is pushed...which ever comes first.

I think it is more common on the heavy duty vehicles, I know Ford has it on their Super Duty's. When hauling heavy trailers, its nice to know that your truck won't roll back on you when you let go of the brake pedal.

Mark
 

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Get this...

I got confused between my wife's Equinox and my Traverse. The Equinox DOES have hill asset. That on a smaller SUV but not on the Traverse? Go figure.
 

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Traverse's transmission is doing this on purpose. It saves fuel by not using the brakes to hold the engine and transmission in place. The transmission is basically going into neutral stat under braking/stopped. So it will slip until it has power returned to the transmission from the engine.

This is not a new thing they have been doing this in cars for years. The fuel millage on the Traverse is the biggest concern for GM so I'm sure they used every trick in the book on it.

You will only notice it oh a hill it works seamlessly on lever surfaces.
 

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I am not sure how the Traverse saves fuel by not holding the brakes? The engine can still be in a type of neutral state at a stand still to save fuel, but that doesn't really have any bearing on the Hill Assist feature. If it did save fuel economy, you know for sure they would not have it on the Equinox. My parents just bought an '10 Equinox, and it gets 6.1L/100km!!!
 

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i think he meant the engine would have to work harder to provide higher line pressure-- the higher the pressure-- the more ability the trans has to 'hold' the vehicle ...

thats what I understood.
 

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Ever listen to your engine when you take your foot off the brake while sitting at a light and not get your foot onto the gas immediately? You can hear the engine revs drop as the trans/torque converter starts to 'grab' again. Time and again I notice this phenomenon, and no - it's not because my A/C clutch cycled on (does it with or without A/C running).

So there's definitely something to the 'loose' torque converter and fuel economy notion. If your foot is on the brake and the vehicle is not in motion (i.e. not slowing down), then they likely have the trans programmed to let the engine freewheel instead of working against the trans/torque converter while basically at a stand-still anyways.

As for the rolling on a slight grade when transitioning from brake to gas pedal... it's purely a matter of the vehicle operator controlling their vehicle. People that drive manual shift are thoroughly familiar with "holding" their vehicle on slight grades by use of clutch/gas/brake pedals. Nothing new there, it's the "expectation" you've built up in driving another automatic vehicle with different setup of weight, trans gearing, torque converter stall, etc.

NOTE: As a driver, if you go to take your foot of the brake pedal, you sure as anything should be ready for your vehicle to move because you are *not* holding it with the brakes! Pretty simple right? Particularly when you're towing.

My Pontiac Pursuit doesn't suffer from this, but it's a 'grocery getter'. This Lambda is a 2+ ton vehicle, not a lightweight Pursuit, Civic or Festiva. Think about if you saw the Wile E. Coyote put a 2+ ton Acme brand weight on a cart with wheels and set it on a slight grade we all know what would happen right?!?!

If anyone wants to pull the "safety card" on this as being a design issue, then they should also look at the brake pedal too. It's designed to work a certain way as well.j

<stepping down of my soapbox now> :p
 

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Yes it is a mechanical system with the torque converter. I can't for the life of me remember what they system is called or I could look up more info. I saw it on a car show once. It took me no time at all to realize the Traverse was using this system.

It's done with the springs in the torque converter when the engines slows it disengages the friction plates and when the engine spins back up they re-engage.

Funny how thing change I remember my old 76 Camaro just forcing the crap out of the brakes and rocking the car when the engine revs would change at stop lights.
 

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You may want to check with your dealership on these two bulletins from GM

2010 CHEVROLET TRAVERSE [103100 POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM, PCM)]
Bulletin Date: Uncertain > Added to NHTSA Database: 06/25/2010
Summary PONTIAC/SATURN/BUICK/GMC/CHEVROLET: TRANSMISSION CALIBRATION UPDATE. A SERVICE PROCEDURE TO REPROGRAM THE ECM AND TCM ON CERTAIN MODEL VEHICLES. THIS NEW CALIBRATION WILL IMPROVE TRANSMISSION SHIFT CHARACTERISTICS FOR DOWNSHIFT HESITATION
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2010 CHEVROLET TRAVERSE [103100 POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM, PCM)]
Bulletin Date: Uncertain > Added to NHTSA Database: 03/24/2010
Summary BUICK/CHEVROLET/HUMMER/GMC/PONTIAC/CADILLAC/SATURN: TECHNICIANS MAY FIND DTCS P0601, P0603, P0604, P062F OR P1621 STORED IN THE TCM AS AN ACTIVE OR A HISTORY CODE. SOME OF THESE DTCS CAN ALSO BE SET IN THE ECM OR FPCM. MAKE SURE THAT YOU
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Does not sound like those are related to the rolling back...

but on the Acadias, Enclaves, Outlooks-- when they came out people complained of the trans shifting/operation...
they eventually had software updates- and in the end reported LOWER mpg's.

for my 2010- I have no complaints about my trans operation.... and I LOVE my MPG's.
id be silly to have a software update that could possibly lower them.... :eek:
 

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FWD Transmission issues.

Does anyone know if either of those 2 updates "clear up" the major hesitation problem that occurs when you depress the gas pedal all the way in attempt to pass another vehicle? I don't know if it's related, or anyone else experiences the problem, but when I depress the accelerator all the way, instead of immediately going forward, the SUV does a major hesitation before "kicking in"... at which point you're pushed back against the seat roughly. Every time I've gone back to the dealer (3 times since I've owned this) I bring up the hesitation problem. They tell me they can't find anything wrong with it. Today, I rented a Traverse while mine was in the shop getting worked on (not for the trans), and lo and behold.....the same problem. situation: doing 60 mph on highway, go to pass someone and depress gas pedal all the way down, car does major hesitation, then boom....takes off like a shot. I have never experienced this before in any vehicle that didn't have a problem, usually carburetor related. This happens all the time when the pedal is depressed quickly. If you slowly depress the pedal, everything has "time" to get in sync so it's not an issue. I am an aggressive driver and subsequently experience this every day......not the least bit enjoyable. Also the reason, when asked how I like the car, the first thing I say is "very much, except for the transmission". I never seem to get to the next thing. It's funny when you mention transmission issues, folks say "never mind"! By the way, both of these vehicles were FWD's, mine an '09, theirs a '10, if that makes a difference.
 

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Be less aggressive with your driving and the problem goes away.

Bob
 

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sounds like youre in 6th gear-- and you suddenly want it to go down to 3rd etc....
Have you tried- manually shifting to L to force the trans to go straight to 4th....? maybe this is more to your satisfaction?
 

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Re: FWD Transmission issues.

gpdanno said:
Does anyone know if either of those 2 updates "clear up" the major hesitation problem that occurs when you depress the gas pedal all the way in attempt to pass another vehicle? I don't know if it's related, or anyone else experiences the problem, but when I depress the accelerator all the way, instead of immediately going forward, the SUV does a major hesitation before "kicking in"... at which point you're pushed back against the seat roughly. Every time I've gone back to the dealer (3 times since I've owned this) I bring up the hesitation problem. They tell me they can't find anything wrong with it. Today, I rented a Traverse while mine was in the shop getting worked on (not for the trans), and lo and behold.....the same problem. situation: doing 60 mph on highway, go to pass someone and depress gas pedal all the way down, car does major hesitation, then boom....takes off like a shot. I have never experienced this before in any vehicle that didn't have a problem, usually carburetor related. This happens all the time when the pedal is depressed quickly. If you slowly depress the pedal, everything has "time" to get in sync so it's not an issue. I am an aggressive driver and subsequently experience this every day......not the least bit enjoyable. Also the reason, when asked how I like the car, the first thing I say is "very much, except for the transmission". I never seem to get to the next thing. It's funny when you mention transmission issues, folks say "never mind"! By the way, both of these vehicles were FWD's, mine an '09, theirs a '10, if that makes a difference.
I've been doing some testing related to your question. I have a 2010 AWD (built (9/09). When I go full throttle at 60 mph, I can see on the tach each downshift for a split second before the next downshift, which ends up in 3rd gear. I don't get a big bang as it might if it downshifted directly to 3rd. The hesitation I experience is similar to what I've had in my past automatic trans cars. The Traverse starts picking up speed right away as the downshifts start. As 5th is selected, there's a split second of 5th gear acceleration before 4th is selected, same with 4th, then 3rd takes over and holds there.

My dealer has performed no trans flashs I know of. Maybe a trans flash would help you. I hope you get it shifting as you'd like.
 
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