2007 Denali transmission question.

[KMeloney]

I've documented many times here just how much I can't stand the tranny in my '09 (the 6-speed). Sounds like you don't have the 6-speed, but that you DO experience all of the issues that I do that make me hate my tranny.

A BlackBear tune will help, but will not eliminate the things you don't like.

No additive or anything will help, either -- so, I wouldn't chase those remedies.

I had no issues with the tranny in my '02. Going to the '09 tranny from the '02 was a real disappointment. Heck, my wife's mini van shifts like a dream. Why can't the Tahoe?

The concerns you have with your tranny appear to be part of the nature of the tranny and the computer, and not something that has failed.

To reset the ecm's learning, try disconnecting the battery overnight, and then put the truck through its paces the next day.

 

[cgraydotcom]

Thanks for that reply. Mine is the 6 speed, like yours. I found that driving it in towing mode eliminates some of the jerk and lag I get it normal mode. My understanding is that the TCM uses my driving habits to determine its function, and there are times I just cruise along, and other times I'm driving it like a race car. Maybe I'm confusing it! Lol.

Does it seem like a common problem that goes mostly unnoticed then? Just wondering now if they all do it to some extent. Will a tune override the learning function, or will it revert back over time? Not sure if I should buy a tuner and do it myself, or have it done.

Thanks again!

 

[KMeloney]

If you have the 6-speed (which I thought I read wasn't around under '09), then you and I are experiencing the exact same things, so much so that I've used some of the same wording and the same circumstances to describe the conditions. So, either you and I (and a bunch of others) have common failures in our trannies, or the design/function is just bad, and some folks are less bothered by it than others. I maintain that it's the latter.

There are a couple things going on. There's the tranny, and then there's the fuel management interference, which affects shift points and throttle response. And your learned driving style determines a lot of this. My understanding is that a BlackBear tune can tune out all (or most) of one annoying aspect (is it the torque management?) but not the other (I can't recall which was which here). So, whereas they can make it so that the truck doesn't leave you in the path of an oncoming train when you step on the gas and the truck bogs and doesn't go anywhere, they can't make the tranny completely smooth and free of annoying up/downshifts at bad times (they CAN move shift points, though to make it drive much better).

You're not confusing your truck with your driving style differing. It's my understanding that it uses a RANGE of driving [style] to determine how it behaves. For instance, when you gather info for a tune from BB, you're to include WOT blasts along with your normal driving. It's on the whole range of driving that a tune can be made custom for you.

Not sure exactly what your last question is, but I'd 1) recommend a BlackBear tune, and 2) if you can have Justin tune your truck in person, then I'd go for it. I had Justin make a tune for me via email, which is the other way for him to tune your truck if not in person. I'd just OPT for an in-person tune, given a choice between the two. Either way, your truck will drive better.

Again, the BB tune can clean up some aspects that currently bother you, but not all.

 

[cgraydotcom]

I believe the 6 speed tranny was installed on the 2007 Denali, and on 2009 and up Tahoes and Subs. Mine is the 2007 Denali. Nice to know they started putting it in everything. It does get pretty good mileage tho, for a bus. So there are things to be happy about.

Maybe its just that there is a lot more "stuff" inside that transmission. More gears, etc. And they just ran out of space to make things move perfectly smooth. I guess if it doesn't lay in the road when I stomp the gas, or cost a fortune to rebuild every year, I can build a tolerance level.

As far as a tune, my question was whether to have Justin do it, or have him send me what I need to do it myself. I assume I would need to purchase some sort of unit do accomplish this. Maybe I need to even if he does it. I have no clue, other than wanting to do it. So any information you can give me on getting it done would be greatly appreciated.

 

[Denali0229]

Yes, the 07 Denali definitely has a six speed. Justin confirmed this to me during my tune. I think BB can work out most of the shifting issues. They did for me but the issues aren't completely gone. From time to time I still get that "slam" when I press the gas while I'm coasting. I've tried changing how I drive or accelerate and that seems to help but like someone mentioned, I think its a tranny issue more than anything.

 

[soulsea]

Drew, after your tune does it still bog down/hesitate tween 1>2>3?

 

[jason952]

My dad just had this problem and it was the motor mount, fixed the knock

 

[Denali0229]

Serge, the shifts are incredibly smooth and the truck is much more responsive. I don't have the lag most people talk about which was definitely there pre-tune. Not sure if that answers your question. PM me if you have a specific question and I'll do my best to answer it.

 

[soulsea]

Serge, the shifts are incredibly smooth and the truck is much more responsive. I don't have the lag most people talk about which was definitely there pre-tune. Not sure if that answers your question. PM me if you have a specific question and I'll do my best to answer it.

Question answered ... thanks bud.

 

[JennaBear]

I have the same problem, when you're coasting then give it gas, it feels like it slams into gear. A BB tune helped but it seems as though its come back. I'm going to try reflashing my tune b/c that seemed to help last time but I know what you mean and it concerned me. I have the same year and model truck too.

Tunes don't change other than if someone flashed over it. Send us a log of your Denali, there may be an underlying mechanical issue that we can help point out.