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lzwhb, it sounds as if your last transmission project on the '08s is a RESOUNDING success! First of all....THANKS so much for your hard work. Dare I ask if you can comment on the apparent fact that the flash actually doesn't degrade mileage as we have been warned, but in many cases actually INCREASES mileage. I am about ready to jump for this flash, but am still concerned that GM says it may result in a decrease in mileage. The shifting really doesn't bother me that much, but if the flash actually does INCREASE mileage, I most definitely want to go for it! Will your bosses let you comment further on this issue? Nod once for yes....twice for no. Thanks for your support! :thumb: :cheers:
 

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I'm thinking that "In theory" this flash should degrade fuel mileage since it raises the shift points for the transmission.

However, the original programming and EPA testing regimen cannot account for the "Human Factor". We, drivers, want a vehicle to respond when the accelerator is pushed. The original programming, with its quick upshifts and torque converter lock-up starting in 2nd gear, just frustrated many drivers who then, wanting their vehicle to respond, would have to mash the gas pedal which would result in the transmission eventally downshifting, rpms to jump up, and the vehicle taking off. So you now have a situation where you have a combination of significant throttle input and high rpms which results in detrimental fuel mileage.

The update allows the transmission to hold each gear longer with less throttle input, which results in a much more responsive vehicle. Even though the engine may be turning more rpms now, there is still less throttle input from the driver since he/she is getting the response that he/she wants from the vehicle. Those people that were frustrated by the original programming responsiveness and overcame it by "flooring it", now don't have to depress the accelerator as much and are therefore getting better mileage.

Computers and algorithms are pretty neat, but they still cannot tell what we "want". They cannot account for the "Human Factor". :cheers: The change in mileage will depend entirely upon how your particular driving habits adjust to the new transmission programming. I have a feeling that when I get this update, my wife's mileage will increase since she is one that is frustrated with how the transmissions responds now and tries to overcome the lack of responsiveness by "stepping on it". ;D I, on the other hand, would likely see a decrease in mileage as I don't drive the vehicle as aggressively as the wife does. But since she drives it 90% of the time, we will likely see an overall increase in mileage.
 

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GeoHawk said:
Computers and algorithms are pretty neat, but they still cannot tell what we "want". They cannot account for the "Human Factor". :cheers: The change in mileage will depend entirely upon how your particular driving habits adjust to the new transmission programming. I have a feeling that when I get this update, my wife's mileage will increase since she is one that is frustrated with how the transmissions responds now and tries to overcome the lack of responsiveness by "stepping on it". ;D I, on the other hand, would likely see a decrease in mileage as I don't drive the vehicle as agressively as the wife does. But since she drives it 90% of the time, we will likely see an overall increase in mileage.
Well said! I think you hit the nail on the head.:clap:

Dave
 

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ccaats said:
lzwhb, it sounds as if your last transmission project on the '08s is a RESOUNDING success! First of all....THANKS so much for your hard work.
Ditto here. You have been a trooper listening to all the complain and some personal attacks. You stayed around anyways and thanks for your part in getting this last update done. Now you just need to get GM to make it more public, so they won't lose those customers which are unhappy but don't know about the update.
 

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I was at the dealership Monday for an oil change and asked about getting the transmission re-calibration and they of course try looking it up on the VIN number.

They are a bunch of good eggs so I will take the specific TSB to the service manager and have him get it done for me.

p.s. Thanks.
 

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GeoHawk nails it. If GM where to make this a mandatory recall they would have to lower the MPG numbers of the vehicle based on the scientific EPA test, and perhaps even open themselves to class action lawsuits from those who would say their vehicle no longer meets the MPG numbers given at the time of purchase. The vast majority of us who have had the update done however don't drive our vehicles like some EPA test and have found that the smoother response of the throttle after the update allows a fuel savings that NEGATES the loss of MPG from holding gears longer and allows for the overall MPG of the vehicle to remain the SAME or BETTER than before.
 
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