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Transmission shifting

4324 Views 9 Replies 6 Participants Last post by  RMneanCA
I have about 2500 miles on my Canyon and have noticed considerable confusion of the transmission when driving through the city at 25 - 35 mph as to whether it wants to stay in 2nd gear or go to 3rd.
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I have about 2500 miles on my Canyon and have noticed considerable confusion of the transmission when driving through the city at 25 - 35 mph as to whether it wants to stay in 2nd gear or go to 3rd.
Yes these transmissions like to float in between gears. They shift depending on mph instead of rpms. I really want to get to my tcm tuned to fix this issue, notice it a lot around 50mph when not going into 6th.
I have about 2500 miles on my Canyon and have noticed considerable confusion of the transmission when driving through the city at 25 - 35 mph as to whether it wants to stay in 2nd gear or go to 3rd.
For the first few thousand miles mine did that at around 25 MPH. I took it to the dealer and was told that these have an adaptive transmission and as soon as it learns driving habits it will stop. I now have just under 20k miles and it stopped soon after my visit to the dealer. If different people drive it then it will take longer to learn habits.
That shifting at a certain mph is also common on the Allison transmissions for the 6.6 Duramax's. Mine would do that, which I actually found nice usually. What Sappergod said about the transmission being adaptive and learning is also true. The TCM (Transmission Control Module) and ECM (Engine Control Module) are both adaptive and learn your driving habits. If you ever get them reset, they are on Fast Learn I believe (was how my 6.6 was after getting it tuned) for so long. I don't know the time frame. Then they switch over to Slow Learn or whatever they call it for the rest of their life unless they get reset again.

mrbones mentioned getting his tuned. DuramaxTuner has tunes for them that change the shift points. The main points being that the RPM's don't run up so high before shifting, which means also that you get into 6th gear quicker at highway speeds.
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Hello Diesel Bill,

I can certainly understand your frustration with this situation. Our team welcomes the opportunity to look into this matter further on our end. If interested, please send us a private message with your VIN, current mileage, full contact information and name of involved dealership.


Best regards,

Anthony J.
GM Customer Care
That shifting at a certain mph is also common on the Allison transmissions for the 6.6 Duramax's. Mine would do that, which I actually found nice usually. What Sappergod said about the transmission being adaptive and learning is also true. The TCM (Transmission Control Module) and ECM (Engine Control Module) are both adaptive and learn your driving habits. If you ever get them reset, they are on Fast Learn I believe (was how my 6.6 was after getting it tuned) for so long. I don't know the time frame. Then they switch over to Slow Learn or whatever they call it for the rest of their life unless they get reset again.

mrbones mentioned getting his tuned. DuramaxTuner has tunes for them that change the shift points. The main points being that the RPM's don't run up so high before shifting, which means also that you get into 6th gear quicker at highway speeds.
For the first few thousand miles mine did that at around 25 MPH. I took it to the dealer and was told that these have an adaptive transmission and as soon as it learns driving habits it will stop. I now have just under 20k miles and it stopped soon after my visit to the dealer. If different people drive it then it will take longer to learn habits.
Thank all of you for your insight of what might be going on. I did read right after I purchased the truck that it had driver adaptive learning qualities but hey it will have fun trying to learn mine because I never driver it the same at any time... lol.
Now back to being serious I find annoying when the driveline clunks around 4 or 5 times before it decides what gear it wants to be in. It's really embarasing when you have a Ford guy in there with ya too.
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Hello Diesel Bill,

I can certainly understand your frustration with this situation. Our team welcomes the opportunity to look into this matter further on our end. If interested, please send us a private message with your VIN, current mileage, full contact information and name of involved dealership.


Best regards,

Anthony J.
GM Customer Care
Anthony, did you happen to get my message/reply? I am not that great with this computer stuff.
Thank You!
Diesel Bill
Good afternoon Diesel Bill.

We apologize for the delay in response, but unfortunately, we did not receive a private message from you. If it’s more convenient, please send us an email with the previously requested information to [email protected]. Hope to hear from you soon!

Thanks,

Bret B.
GM Customer Care
Yes, I have the same transmission issue. I have just learned to go faster then slow down.

for me, mid to high 20's runs high but when you hit 30mph it shifts to low rpms

same for 24/25 mph (side note is it not neat that you can long your Cruise control at 24mph)

I normally have to go up to 42mph for it to shift and relax then lower it down to 40mph
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