And update for the better? Clunk be gone?

[Arnoldthepig]

I was considering a tune, but after reading this thread, I made my appointment for Monday Oct 12th to have the update installed. I sure hope this helps the low speed shifting parameters. I have owned my truck for 18 months and still cant get use to the way it drives at low speeds. Fingers crossed!!

[EXSlider400]

I dropped it off this morning I just hope that the new program does not affect the new brighter lighting. I don't know if that is even part of same computer....

[Bonker]

I have an appointment for Next Wednesday the 14th October to have this re-flash done, I am hoping the drivability will improve with this update.

[GMMediumDutyMQ]

I dropped it off this morning I just hope that the new program does not affect the new brighter lighting. I don't know if that is even part of same computer....

It shouldn't. That's handled by the body control module. This flashes just the transfer case control module.

[ewbldavis]

Not due for oil change, and I don't notice anything too unusual with the way mine shifts. At 3500 miles, I haven't really broke it in yet.

 

Plan on oil change at around 5K, and I will be curious to see if there is an update (bought mine in May). If so, curious if I will notice a difference.

 

Also need to mention the dreaded vibration. Seems intermittent at around 68 MPH. Trying to pay attention without assuming it is vibrating because I read about it here!

[EXSlider400]

It shouldn't. That's handled by the body control module. This flashes just the transfer case control module.

Thanks for the info.

[Hat]

After driving around for a day with the new update, highway and city, I can tell a significant difference. The truck feels more composed and the weird clunk on downshifts and surge on upshifts are pretty much gone.

[GMC-AT]

What was the exact update they did - do you have a reference number?

[Hat]

Service Update Bulletin 15304

[CounterMeasure]

After driving around for a day with the new update, highway and city, I can tell a significant difference. The truck feels more composed and the weird clunk on downshifts and surge on upshifts are pretty much gone.

 

Could it be the update puts the tranny back in learn mode, which starts off very conservative?

[stevev]

Service Update Bulletin 15304

 

any more specific details about this as far as what years or build dates that the update applies to?

 

I ran my VIN on the GM recall website and nothing comes up. June 2014 build date here.

[Hat]

 

Could it be the update puts the tranny back in learn mode, which starts off very conservative?

Maybe, but my receipt does state the update improves drivability. Ill upload a picture when I get home. Truck has 10,500 and I've noticed the clunk since day 1

[Hat]

 

any more specific details about this as far as what years or build dates that the update applies to?

 

I ran my VIN on the GM recall website and nothing comes up. June 2014 build date here.

I think it may apply to 4x4 only, Nothing came up when I searched on that site. When I called the dealer they were able to pull it up with my VIN

[Doobs41378]

Maybe, but my receipt does state the update improves drivability. Ill upload a picture when I get home. Truck has 10,500 and I've noticed the clunk since day 1

I already uploaded the picture if you look back a few pages.

[GMMediumDutyMQ]

Right. But the wording on that (and the SI bulletin) is "...other transfer case control issues for overall improved drivability." Implying the cause/ fix is still only in the transfer case. Having watched the tech perform this on my truck, I can attest to the fact that he only went into the program transfer case menu -- nothing for ECM/ TCM/ etc. And yet -- my truck feels smoother, even in 2WD...

I guess it could have been something in the previous transfer case control programming that worked against NVH perfection with the transmission or something, but until someone goes through line by line of code, I couldn't tell you. That said, I know better than to look a gift horse in the mouth...I'll take this improvement! :-)