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Discussion Starter · #1 ·
I have a 2009 acadia with 7000km on it and I'm getting a hesitation when I go to pass another car. When I press on the gas pedal to pass, it hesitiates so bad that the rpm's red line but there's no acceleration. It's like it's skipping or cannot find the right gear. It seems if you push on the pedal slowly it doesn't do it only when you punch it hard. I had a pontiav G6 before this vehicle and you could punch it as hard and fast as you wanted and it would respond. Anyway I just was wondering if anybody else has had this same problem with there acadia. I'm going to take it into the dealer to see if they can find out what the problem is. I don't have much confidence in my dealer though.

Moderator edit
Similar threads merged. See also the sticky in the TSB section:
Transmission Reflash TSB Info For 2007 Through 2009 models[/color]
 

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Re: transmissin hesitation when pedal is punched

Wow this is the first I have heard with the 2009 models having this issue... I dont want to sound like an :bootyshake:
but you are sure you have an 09 right?
There was a lot of issues with the transmission shifting on the 07 and 08s, that was corrected or made better with a transmission flash.

I am adjusting your thread title to include 2009[/color]
 

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Discussion Starter · #3 ·
Re: 2009 transmissin hesitation when pedal is punched

Yeh I'am very sure I have a 09. They probably haven't changed anything from the 08.
 

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Re: 2009 transmissin hesitation when pedal is punched

tydunn said:
Yeh I'am very sure I have a 09. They probably haven't changed anything from the 08.
I am pretty sure that was addressed with the 09's. They had to make some adjustments I believe with the new engine.
Geohawk would be able to say for sure.
Blue you have an 09, thoughts?
 

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Re: 2009 transmissin hesitation when pedal is punched

My husband and I were just making the same comments about our '09 the other day. We get about a second and a half lag before it decides to go, then it really goes. Let me know how you make out with your dealer because if there is a fix, we'd be interested for sure.
 

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Re: 2009 transmissin hesitation when pedal is punched

Even with the software updates, the tranny still prefers to stay in high gears. Its all about fuel efficiency. How else would a vehicle this size really get 24 MPG.
 

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Re: 2009 transmissin hesitation when pedal is punched

mikemu said:
Even with the software updates, the tranny still prefers to stay in high gears. Its all about fuel efficiency. How else would a vehicle this size really get 24 MPG.
Bingo! Just yesterday I was driving my Enclave, had my buddy in the car, and we pulled out into traffic, and then I decided to push harder on the gas to flow with traffic better, but didn't punch it. At a point, the transmission downshifted, and we took off...my buddy was reaching for something on the floor, and then was pushed back, and looked pretty funny trying to reach the floor....plus, he didn't have his seatbelt on, so the warning started to ding...it was all a bit funny. Anyway, my point to this rambling is...if you use the L all the time, which I don't do, but will try to remember to more often, you can avoid some of the lunges with downshifting. For example, had I used it yesterday pulling out, I could have eased out, not punching it, and kept it in first gear till I was in the traffic flow, then accelerated slower. But instead, it had shifted into 2nd, or 3rd, and when I needed more power, it had to downshift. There's a time and place for either using D or using L...just have to get used to it. I rarely use the L with the tap shift, but will try to do it more.,
 

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Re: 2009 transmissin hesitation when pedal is punched

Welcome 09Enclave - how does the vehicle handle snowy winters in Mich? I opted for the FWD only as I prefer less mechanical complexity and slightly better fuel mileage.
 

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Re: 2009 transmissin hesitation when pedal is punched

No doubt this vehicle has the worst transmission programming of any car I have ever owned. It is my first six speed auto, but I have owned V6's with 5 speeds and they have been very responsive to the throttle. I think this poor real world performance is a result of GM trying to get high mpg numbers on the EPA cycle. What works in test conditions does not translate into good performance under actual driving conditions. The transmission ratios do not seem very well suited to the torque curve of the engine This alone would make me reconsider the purchase of another Acadia or one of it's siblings.
 

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Re: 2009 transmissin hesitation when pedal is punched

big bear craig said:
No doubt this vehicle has the worst transmission programming of any car I have ever owned. It is my first six speed auto, but I have owned V6's with 5 speeds and they have been very responsive to the throttle. I think this poor real world performance is a result of GM trying to get high mpg numbers on the EPA cycle. What works in test conditions does not translate into good performance under actual driving conditions. The transmission ratios do not seem very well suited to the torque curve of the engine This alone would make me reconsider the purchase of another Acadia or one of it's siblings.
so everyone seems to think this is the same problem that everyone was complaining about with the 07 and 08 models.... So can the transmission flash be done to the 09's as well then?
 

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Re: 2009 transmissin hesitation when pedal is punched

Aren't these transmissions supposed to learn your driving style over time? I have little issue with my '07 shifting either up or down. I wrote in the Forum before about using 'L' and thumbshifting when I'm in town. I rarely start out in 1st, rather I start out in a gear conducive to the average speed of the roadway. For example - I'll use 3, when 25 and under (miles per hour for you folks up north), 4 for 40 and under, and 5 for 50 and under. The transmission runs through all the gears up to the chosen gear and downshifts pretty well when I need it to do that. Frankly, my fuel mileage has been consistently between 18.5 and 19.5 mpg at an average speed of around 30 mph.

One thing I don't do is lolligag around to get up to the cruising speed. My driving instructor taught me to step out smartly, get up to speed and cruise (thanks, Mom). I hate it when I get behind someone who takes 1 mile to reach 45 mph.

that's enough for now! :soapbox:
 

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Re: 2009 transmissin hesitation when pedal is punched

My wife's Acadia had 2 trans flashes, one in 07 and the other in 08 because of lag at certain periods when need more zoooom! I don't have any more lag issues. Perhaps some people are overly critical as I prefer the 6 speed for better mpg. Wait till the lefties in Washington mandate us to buy battery vehicles............!
 

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Re: 2009 transmissin hesitation when pedal is punched

Using the L feature doesnt allow you shift the gears. You can not select L and push + to 3 and start in 3rd gear. The L Limits your max gear, if you select 3 and drive down the road, you are only holding 3rd gear longer, until you shift.
 

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Re: 2009 transmissin hesitation when pedal is punched

Hard to believe that a tuner hasn't taken up the task of developing software/PCM reprogramming for the Acadia engine.
 

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Re: 2009 transmissin hesitation when pedal is punched

I've goosed mine and no probs.
 

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Re: 2009 transmissin hesitation when pedal is punched

bonk1313 said:
Using the L feature doesnt allow you shift the gears. You can not select L and push + to 3 and start in 3rd gear. The L Limits your max gear, if you select 3 and drive down the road, you are only holding 3rd gear longer, until you shift.
bonk, I think that's what I said in the post. you go from 1st to your selection, then stay there until you stop and start out again.

But...I must add an "ers" after bonk about your shifting gears comment. One can "thumb shift" their Acadia up and down all gears if you want to do that. I do it in WV and on curvy MD roads a bunch of times. You can wind 'er up tight on short straghts, save your brakes and get that "sports car feel!!" Need lessons, I'll show you how it's done.
:police:
 

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Re: 2009 transmissin hesitation when pedal is punched

mikemu said:
Welcome 09Enclave - how does the vehicle handle snowy winters in Mich? I opted for the FWD only as I prefer less mechanical complexity and slightly better fuel mileage.
I'm happy with how it does in the snow, for just FWD....however, I've only owned FWD for so long, never had a 4x4 or AWD to compare. These Lambdas are high enough for good ground clearance, so that helps in deep snow. The only thing I don't like is how low the front fascia hangs, I feel like it will hit in deep snow. (They should have made a removable lower part that comes off for winter...put it back on for summer for better aerodynamics)

As for the tranny, everyone wanted GM to have a 6-speed, (cried :'( and whined about how dated the 4-speeds were), and now people don't like how it shifts. With that many gears, it's no wonder it acts like it does. Granted, they changed the 07's and 08's with the reflash, but I think they will only be as good as they are....the only way to get real performance is with fewer gears, I would tend to think. But, the 6-speeds are good for fuel economy...can't have it both ways. I think they perform pretty darn well for what they are..these are not performance vehicles, but they have enough to make them fun to drive.
 

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Discussion Starter · #18 ·
Re: 2009 transmissin hesitation when pedal is punched

Does anyone know if there is a flash download for the 09 transmissions. As like the 07 and 08.
 

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Re: 2009 transmissin hesitation when pedal is punched

bonk1313 said:
Blue you have an 09, thoughts?
I remember reading a thread here where someone stated the transmission had been improved over the 2008 model. I'll look into it & update here if I find something definitive.

As I've noted elsewhere, and as mikemu said above, these vehicles are relatively heavy. One thing I've also found is the torque converter (device that connects the motor to the transmission) is "loose", i.e. you will see more RPM before the vehicle starts to move, and you will also see it roll back while in drive and on a hill (this took Mrs. Blue some getting used to). Accordingly, when you go to rapidly accelerate, the engine will rev higher than another vehicle with the same combination but a "tighter" converter.

I don't drive our (her ;)) Acadia much, but when I have it does need to switch gears and really hit fairly high RPM to do a 50-70 type pass on a two lane road.

I found this on AOL Autos, supposedly regarding the 2009 model:
...the Acadia's transmission can occasionally be hesitant to downshift, blunting passing performance somewhat.

-- Edmunds.com


The online GM parts catalogs I've looked at don't list 2009 models, so I can't tell if the transaxle is a different part number.

Here is a document link (.doc file) from GM Media regarding the 2009 transmission:
Link

Relevant info:
NEW TRUCK APPLICATIONS:
The 6T70 (MH2,MH4) will be available in 2009 for the following truck models: Suzuki XL-7 and Chevrolet Captiva Sport. These models are all teamed up with the 3.6L V-6 VVT (LY7) engine. In addition, the 6T70 (MH2, MH4) models are available in the Saturn VUE, Chevrolet Equinox, and Pontiac Torrent models.

The 6T75 (MY9, MH6) will be available in 2009 for the Chevrolet Traverse model mated to the 3.6L V-6 VVT DI (LLT) engine. In addition, the 6T75 (MY9, MH6) models are available in the Saturn Outlook, GMC Acadia, and Buick Enclave models mated with the 3.6L V-6 VVT DI (LLT) engine.


The document is somewhat confusing, as it says "FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES" on page 1, then lists what I copied above. The next page says "Carryover from model year 2008 features and benefits are listed below:"

Based on this, I'd say the only changes were some applications.

According to the Wikipedia entry, the 6T75 has been made since 2006, so the transaxle is the same model for all years.
 

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Re: 2009 transmissin hesitation when pedal is punched

I'm with you 09Enclave. We didn't purchase this vehicle to win drag races. It is a terrific vehicle, lots of cargo space, handles more like a car than an SUV and gets halfway decent MPG. What more can you ask for.
 
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