[tomme12]

Before I had my 2010 AWD delivered, I told the dealer to load the latest software update for the tranny. Im not sure if they did or not. I have been able to repeat this scenario a couple times now. The basic concept is that the tranny is not shifting into higher gears when you left off the gas or are coasting down a hill. Sometimes it does, sometimes it does not.

For example, i go up a decent hill at about 40, maybe 1/2 mile up, coast about 3/4 mile down. I keep it around 40-45, (40mph is speed limit) When I come down this hill, sometimes it does not upshift when Im coasting. I see my RPMs at almost 2k, if I tap the gas, it finally upshifts and I see my RPMs drop down.

I noticed also, it happened on a flat street, went from 35 mph, let off the gas to coast into the stop sign.. and the RPMs were again, not dropping until I tapped the gas and it dropped.

I wish there was a way to see which gear you were in live on the dash.... And also does anyone know if OnStar can report on your tranny software version?

 

[rbarrios]

I think what youre experiencing- is normal for this trans.
from quickly reading your post... mine appears to do the same thing.

I have noticed that you let off the gas- and in other (non 6 speed trans) the trans will shift to a lower gear.
but not the trans in the Traverse.
when I drive- and I see a long straight road- where I can coast--- and I can take advantage of a lower gear-- I will keep my foot on the gas---
normally you expect it to shift- but it wont--- my solution is to step on the gas a little more--- speed up a little--- and then back off the gas-- this will usually force a shift- and rpms drop.

But I have also noticed that the transmission will eventually many times notice that youre coasting-- and will shift back up-- thus causing RPM's to go back up....

I dont think this is bad--- just the way the 6 speeds are setup to utilize speed and the respective gears for best performance (acceleration etc).

I have learned to drive my traverse--- and am happy with the current mileage im getting--- 18-20 mpg in combined city/hwy

 

[bobg1951chevy]

Before I had my 2010 AWD delivered, I told the dealer to load the latest software update for the tranny. Im not sure if they did or not. I have been able to repeat this scenario a couple times now. The basic concept is that the tranny is not shifting into higher gears when you left off the gas or are coasting down a hill. Sometimes it does, sometimes it does not.

For example, i go up a decent hill at about 40, maybe 1/2 mile up, coast about 3/4 mile down. I keep it around 40-45, (40mph is speed limit) When I come down this hill, sometimes it does not upshift when Im coasting. I see my RPMs at almost 2k, if I tap the gas, it finally upshifts and I see my RPMs drop down.

I noticed also, it happened on a flat street, went from 35 mph, let off the gas to coast into the stop sign.. and the RPMs were again, not dropping until I tapped the gas and it dropped.

I wish there was a way to see which gear you were in live on the dash.... And also does anyone know if OnStar can report on your tranny software version?

I'm not certain any trans update was needed on the 2010.

When going down a hill .... "coasting", the trans will not upshift to 6th, instead it will select 5th or 4th to maintain the speed, rather than having the vehicle act like a "runaway". RPM's will be higher when the trans is in a lower gear.

Your trans is working correctly, as you are reporting it.

"Tapping the gas" tells the computer you are accelerating, thereby moving the trans toward the 6th gear position. RPM will drop as trans gets closer to 6th gear.

Understand the trans does some of the thinking for you, does some of the downshifting to maintain a steady speed which ultimately extends brake life, as a result.

Bob

 

[rbarrios]

oh-- forgot to mention--

The Traverse comes with what is basically Descent control....
this is what you may be experiencing- with the changes in gear- or not changing gears when you think it should...

Page 9-26 of the 2010 manual (and 2-25 of the 2009 manual)... says
Automatic engine grade braking....
Automatic engine grade braking assists when driving on a downhill grade. It maintains vehicle speed by automatically implementing a shift schedule that uses the engine and the transmission to slow the vehicle. the system will automatically command downshifts to reduce vehicle speeds- until the brake pedal is no longer being pressed.

(while in Electronic Range Select) grade braking is deactivated.

 

[Narg]

I love this feature. I also like that the vehicle holds the brakes for a 1/2 second on an incline so that you have time to press the gas peddle before rolling when starting from a stop on a hill.

Modern GM vehicles have a lot of nice little features that will spoil you. :thumb:

 

[rbarrios]

thats a new one--- the computer holding brakes for 1/2 second... please elaborate.

Ive seen multiple post from owners complain that on uphills- the vehicle begins to roll backward--- they were unhappy that the 6 speed doesnt hold their lambda vehicle as well as their (fill in brand/model here).

 

[bowtie]

thats a new one--- the computer holding brakes for 1/2 second... please elaborate.

Ive seen multiple post from owners complain that on uphills- the vehicle begins to roll backward--- they were unhappy that the 6 speed doesnt hold their lambda vehicle as well as their (fill in brand/model here).

+1...mine certainly rolls back...

 

[bobg1951chevy]

My Traverse lives mostly on hills and grades of varying degrees ... mine will roll back OR forward in a New York minute, will not maintain a "hold pattern". At times, I need to use the left foot to hold the brake, while the right foot pampers the accelerator.

Bob

 

[quantum]

Narg,

My Traverse does not have hill assist. My parents 2010 Equinox does. So I know what I'm looking for. I have a steep incline by my house and the Traverse doesn't hold. The Equinox on the other hand holds for upto 2 secs I believe (until the gas is hit).

 

[quantum]

Tomme12,

My brand new 2010 shifts the same as yours. I know what you mean about coasting. I have to get used to as well, because my old vehicle used to roll and roll. If I try to approach a stop light the same way I used to, I end up having to press the gas pedal, or I will come up short a couple hundred feet.

I agree with rbarrios about the decent control. That is automatic engine braking. It comes in handy for sure!

 

[tomme12]

Im not sure if I agree with GM on the ascending control option... if im coasting, im coasting for a reason down a hill. Thats what brakes are for.... but I guess now we have 100,000 powertrain, I will use my tranny to slow me down more than my brakes! I was trying to max out my mpgs while coasting. I noticed this morning it was coasting, then downshifted for no reason.... "tapping" the gas kind of defeats the purpose of better mpgs. I will have to try it in "L" with "6" selected and see how it does on the same slope. I guess trannys are "Free" Brakes are not (reverse my thinking on this old motto)

As for the rollback or brake option, I did notice this a couple times. It all depends on the slope... at one stop light, it holds for sure... but other steeper grade lights, not so much....

The downshift happens in my 2006 saturn vue also... drives me nuts. Never happens in a jeep!

 

[rbarrios]

There is alot of people who dont know how to use engine braking on long downhills.
Much much safer to use the engines compression to do the 'braking'.

I sure am not gonna overheat the brakes when I have people in the vehicle with me.

I guess on 'short' downhills- you can pop it into L and leave it at 6... so as not to use descent control

 

[tdk]

Regarding the tranny downshifting while decenidng a hill.

I believe this only activates if the vehicle is in cruise control. That feature has been around a long time in many car makers.

My 09 coasts (and gains speed if steep enough) just fine if not in cruise.

Logically, how would the car know that it should maintain a constant speed and slow down from coasting - if it was NOT set in cruise control?

It would have to make a lot of invalid assumptions that the driver wanted to maintain a constant speed with no accelarator input, and that the car was on a significant hill, and would be in that state for a significant time.

That kind of logic might have been implemented by a former #1 auto maker...

 

[tomme12]

Nope, I was not using cruise control. Im going to drive around L with 6 selected and see how it does. Im curious if the MPG change also.

 

[bobg1951chevy]

The descend contol will activate with cruise ... on ... and descending a hill OR
descending a hill with cruise .... off ... but foot on brake pedal.

Bob

 

[09Enclave]

If I take my foot off the gas, mine will for sure feel like it's slowing down via the transmission. Only if I keep my foot on the gas will this not happen.

 

[rbarrios]

Regarding the tranny downshifting while decenidng a hill.

I believe this only activates if the vehicle is in cruise control. That feature has been around a long time in many car makers.

My 09 coasts (and gains speed if steep enough) just fine if not in cruise.

Logically, how would the car know that it should maintain a constant speed and slow down from coasting - if it was NOT set in cruise control?

It would have to make a lot of invalid assumptions that the driver wanted to maintain a constant speed with no accelarator input, and that the car was on a significant hill, and would be in that state for a significant time.

That kind of logic might have been implemented by a former #1 auto maker...

if youre not using Cruise control--- and youre going downhill---- it will activate Automatic Engine Grade braking if it senses that youre pressing the brakes...

think of it this way---
the computer senses that you are no longer pressing on the gas--- AND you are gaining speed- AND you have now begun to step on the brake and are holding the brake----
it then activates the feature.

 

[bobg1951chevy]

If I take my foot off the gas, mine will for sure feel like it's slowing down via the trasmission. Only if I keep my foot on the gas will this not happen.

What we are speaking of here is tied to the trans operation and function. The descend control "downshifts" the transmission if brakes are applied or cruise is on ..... when going down a grade.

Bob

 

[copperbeech]

I know this doesnt sound right but it is my understanding that it is just recently that there has been a transmission flash (the first one ???) for the 09 MY Lambdas.

It is identified as PI0103 and is described as follows:

Some customers may comment on transmission downshift hesitation, delayed shifting or shifting at the wrong time.

Anyone heard of it and had it done?

 

[tomme12]

I think if GM tweaks this "downhill braking" assistant, we would all get a little better MPGs. It kicks in at really odd points. Almost like a timer. If you hit the brakes three times in a certain amount time around 40, it will downshift, when it should be coasting. I was not picking up speed, it was steady if not dropping by itself.. then it downshifts and Im going slower than I wanted to be.

But the pros are when are wanting to stop, it will downshift all the way down until you come to a stop. Basically it boils down to:

- Save on MPG with coasting vs cost of brakes. Maybe GM decided that brakes were cheaper than MPGs?