GMC Acadia Forum banner

1 - 20 of 42 Posts

·
Registered
Joined
·
179 Posts
Discussion Starter · #1 ·
I'm glad to see the positive feedback from those that have had their transmissions updated. This thread is meant for those that still aren't satisfied even after the update. What more were you expecting or what more do you want? Even those that are satisfied now still might have continuous improvement suggestions. Please feel free to voice your opinions here.
 

·
Registered
Joined
·
16 Posts
lzwhb2 said:
This thread is meant for those that still aren't satisfied even after the update. What more were you expecting or what more do you want?
I mentioned in another post that after the updated, the DIC was scrambled and giving inaccurate data in all fields including the odometer (3 miles shown for approx 15 driven). I never had an issue about the car holding position on an incline, that's what the brake is for. After the flash, the car still over revs and doesn't downshift. Overall, I just didn't see the big difference (so far....it was back in the shop after 20 miles) I was hoping for.

In a nutshell, the car just needs more power. And not just for the rumored Denali version. I don't mind feeling a car shift, I have driven CVT transmissions and hate them. Smooth acceleration is good, but not at the expense of response. I do not like a two second lag from the time I push the pedal to pass (floored) and the car responding. The RPM responds to pedal imput and the engine makes noise....but the acceleration doesn't match the RPM. IE...makes a lot of noise and doesn't move.
 

·
Registered
Joined
·
956 Posts
Sounds like you might have bought the wrong car for your needs. More power is always nice, but at what expense? If I could change anything it would be the weight. I would like to see about a 500 pound diet on the Acadia, but there would be a tradeoff somewhere.
 

·
Registered
Joined
·
16 Posts
big bear craig said:
Sounds like you might have bought the wrong car for your needs.
I'm not expecting a Ferrari, but I would like it to keep pace with the lower powered, 5 yr old minivan we traded for it.

big bear craig said:
I would like to see about a 500 pound diet on the Acadia, but there would be a tradeoff somewhere.
There is a 500# lighter one....it's the Equinox. ;D

A 500# lighter Acadia would have a similar effect as what I wished for above. More power and same weight or less weight and same power, both would produce better performance.
 

·
Registered
Joined
·
100 Posts
Is this a true cvt transmission though? I drove a nissan murano and this doesn't shift anything like it. If I recall, the murano would keep the rpm's constant on heavy throttle to where you didn't see the needle change when the transmission shifted. I know my acadia doesn't shift like this. I think it was really someone twisting the the definition of cvt.
 

·
Premium Member
Joined
·
3,212 Posts
JasonM said:
Is this a true cvt transmission though? I drove a nissan murano and this doesn't shift anything like it. If I recall, the murano would keep the rpm's constant on heavy throttle to where you didn't see the needle change when the transmission shifted. I know my acadia doesn't shift like this. I think it was really someone twisting the the definition of cvt.
It's not a CVT in the Acadia. We have a regular 6-speed automatic.
 

·
Registered
Joined
·
100 Posts
That's good to hear. The salesman at the dealership tried to tell me it was a cvt. I could not find any reference online that it was.
 

·
Registered
Joined
·
12 Posts
sounds like I'm not the only one having these issues.

almost exactly what's happening to us, but we are trying to make sure the dealer didn't give us the wrong patch by mistake.

very frustrating for the wife as she's worried for her safety every time she drives it.
 

·
Registered
Joined
·
16 Posts
Update:

Now that the dealer flashed both modules, it is behaving much better. I'll look forward to driving it some more to get a better feel for the changes.
 

·
Premium Member
Joined
·
3,212 Posts
jason7655 said:
sounds like I'm not the only one having these issues.

almost exactly what's happening to us, but we are trying to make sure the dealer didn't give us the wrong patch by mistake.

very frustrating for the wife as she's worried for her safety every time she drives it.
This could be the same problem you are having. Make sure the dealer is flashing both the ECM (engine control module) and TCM (transmission control module). If they only do one or the other the flash is worthless. Some service depts may not be aware of both modules if they are not familiar with the Acadia. I believe 2007 was the first year GM started using two separate modules, as my 2007 Silverado has 2 modules but my 2004 Silverado only had a ECM that controlled both the engine and transmission.
 

·
Registered
Joined
·
105 Posts
Speaking of modules, is there such a thing as a Body control module? That's what they told me went out when the button on the power liftgate stopped working.
 

·
Premium Member
Joined
·
3,212 Posts
wearefla said:
Speaking of modules, is there such a thing as a Body control module? That's what they told me went out when the button on the power liftgate stopped working.
Yep, there's a BCM too. :ack: Too much stuff to keep track of anymore.
 

·
Premium Member
Joined
·
2,577 Posts
Okay so I got the tranny flash yesterday and drove it to the train station this morning. I've said previously that I was hesitant to get this new update because over the past 12,000 miles, I've learned how to drive my vehicle and make it respond, for the most part, as I wish.

Having said that, this morning I "tested" the tranny on a few of the points I know I had to get used to. I purposely took a turn a bit fast because that's where I most noticed the hesitation in the past... slowing down for a turn and then trying to pick up speed again to keep up with traffic. It didn't hesitate at all. I'm pleased with that. Also, it used to bog down a little bit right around 45-50mph. I'd have to really press the pedal down to pick up speed and that usually resulted in revving the RPMs up there before the vehicle actually took off. That issue seemed to be gone as well.

So overall, I'd say I'm pleased with the update. I didn't feel I necessarily needed it, I'm certainly not disappointed. I <3 my Acadia.
 

·
Registered
Joined
·
83 Posts
Mine's in for the reflash right now, at Flow in Greensboro, NC. I've got them looking at the drivetrain whine, too, plus the manual lumbar popped and stopped working on the driver's seat. They're also doing an oil change with full synthetic, rotating and balancing the tires, plus any other service bulletins or recalls. My service loaner is a base Buick Lucerne. I'm sort of surprised, it's not really any nicer inside than my mom's 06 Impala, and I honestly don't think it's any roomier, either. But, it gets me from here to there, while my Acadia is being serviced, so I can't complain. I feel so mature driving it, lol.
 

·
Registered
Joined
·
662 Posts
Hey Web Raven & NJA Capt. let us know how your mpg does after the flashes. Did you tell your dealer to do the flashes or did they just do them as part of a regular service? I just had my first oil changes and did a tire rotation, but the dealer did not do any TCM or ECM flashes. Of course this dealer also failed to check the air in the tires after they rotated, and I have to see if they reassigned the tire pressure monitors. Maybe I need a better dealership? :whip:
 

·
Premium Member
Joined
·
2,577 Posts
tm59 said:
Hey Web Raven & NJA Capt. let us know how your mpg does after the flashes. Did you tell your dealer to do the flashes or did they just do them as part of a regular service? I just had my first oil changes and did a tire rotation, but the dealer did not do any TCM or ECM flashes. Of course this dealer also failed to check the air in the tires after they rotated, and I have to see if they reassigned the tire pressure monitors. Maybe I need a better dealership? :whip:
I specifically asked them to perform the transmission update when I brought it in for the oil change/tire rotation and to have the bloop-bloop noise and engine whine noises checked out. I'll keep an eye on my MPG. I'm curious to see if it will be affected as well.
 

·
Registered
Joined
·
83 Posts
Just got a call from the GMC service department at Flow; it's ready. I was reassured that they definitely did flash both the ECM and TCM. I also was told that the drivetrain whine is believed to be related to the a/c compressor, but that GM did not have a fix for it at this time, but were working on it, for what that's worth. I'll be picking it up in about 45 minutes, and will post my immediate impressions, as far as driving it the five or so miles to my office.
 

·
Registered
Joined
·
83 Posts
OK, too much traffic coming back to get a full impression, but the shifts feel more linear and precise after the reflash. No odd lags or flat spots. Reset the DIC to make sure there wasn't anything wacky going on, and it appears to be fine. Mileage from there to here, approximately five miles, was a little over 19 mpg. Won't really know if mileage has been impacted at all, until I drive it home, since I already had a pretty good feel for what to expect and can compare.
 

·
Premium Member
Joined
·
2,577 Posts
After driving it from the train station, to the high school, to the dealership to pick up my train pass that I forgot in the rental, and then home... I have to say that the tranny is NOT behaving much differently than it did before with respect to the 45-50mph lag. It's still there. It actually starts between 40 and 45mph. It hits that spot and just doesn't want to accelerate.

I don't think I'm going to bother bringing it back. Like I said, I've learned to drive around it. It's just not worth having my Acadia spend more unnecessary time at the dealership when they're probably just gonna jack it up anyway. If the 20mph issue remains fixed, then I'm good with that.
 
1 - 20 of 42 Posts
Top