Downshifting while passing

[eazy88]

Good Day All,
I just bought a 2015 Yukon XL Denali with the 8 speed and i love everything about the vehicle except for my payment, and the passing power. I was wondering if that is a problem for everyone with a 8 speed 6.2L? Cruising at 65 MPH, i try to put the gas pedal through the floor boards and it will only drop one or two gears. The RPM will go from around 1500 to 2800. I feel that it should drop another gear to get me in the 4000+ range to get some REAL passing power. My last vehicle would pick the lowest gear as long as it wasn't going into redline (even if I only had a couple hundred more to go till red, it would still take me to that gear).

I am sure that a tuner would fix all my issues, but I would like to stay in factory warranty for at least a month or two My service guy seems to think this lazy shifting is the way it should be, but I wouldnt think so considering my 2015 GMC Sierra (5.3) is not at all like that.

Any input would be appreciated!

 

[ezdaar]

Get a Tune. It will solve all your problems.

 

[eazy88]

I was wondering if this is what all Denalis do?


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[Reels]

I have had my tranny reflashed twice. 10/14 build, one of the first eights. It drops down and hits 4000 RPM in a heart beat with this last flash update from the dealer done a few weeks ago. I also notice she gets a lot more peppy using 91 octane fuel and more responsive to the throttle.

 

[eazy88]

Thanks Reels. Was this a service bulletin or do I have to ask specifically for a flash that helps the shifting?


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[Reels]

It was a recall regarding transmission clutch shudder I received in the mail last month. Don't overlook the octane thing though. It makes quite a difference IMHO.

 

[techbrute]

Mine will definitely rev when pushed. Sometimes I feel like it should up shift sooner under power.

 

[eazy88]

Here is a short video of my issue. I made this after my dealership told me I am up to date and there is nothing wrong with my Denali. Each acceleration is full throttle, 1st one as fast and hard as I could, 2nd and 3rd progressively lighter, but still ends up full throttle. https://vimeo.com/135417235


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[Lyon]

Hmmm, mine doesn't seem to have such a problem but I guess I've never really paid all that much attention to which gear it drops into when I floor it. I've never had difficulty passing at highway speeds.

I know the car has some kind of learning transmission controller, maybe it's still learning?

 

[eazy88]

Thanks. And just to let you all know, this 6.2 has never seen anything but good premium fuel. If anyone could floor their 2015i Denali and let me know what it revs to when (safely) passing from 65 mph (100km/h) it would be much appreciated.


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