8 speed trans, reprogram

Crobinson16 · March 20, 2018

Justin based on the photo I posted, does it appear there is a update available for my truck. I put in my vin, but I cropped it out of the picture. Also that's interesting on the tcm swap. So would that me if I had trouble I could swap the original TCM back in with out causing flags for warranty work or would it still show up some how to gm

.justin. · March 20, 2018

There is no way of knowing what version you have without connecting to the vehicle unfortunately. It does appear though, as you indicate, that there is an update.

If you did swap TCMs, then yes, you would be able to swap back without issue.

Crobinson16 · March 20, 2018

23 minutes ago, .justin. said:

There is no way of knowing what version you have without connecting to the vehicle unfortunately. It does appear though, as you indicate, that there is an update.

If you did swap TCMs, then yes, you would be able to swap back without issue.

Would the same gor for the ecm as well or is there no issue with keeping the same ecm and tunning it with out changing the cal ID's. ? Or is there an issue with tunning the ecm and gm being able to see it was tunned.

.justin. · March 20, 2018

1 hour ago, Crobinson16 said:

Would the same gor for the ecm as well or is there no issue with keeping the same ecm and tunning it with out changing the cal ID's. ? Or is there an issue with tunning the ecm and gm being able to see it was tunned.

The Calibration ID numbers won't change with any tuning that is done properly. It is the CVN, which is the first half of the checksum, that *could* change. There are 65,535 possible tune combinations that will result in the same CVN as stock for a particular calibration segment.

Crobinson16 · March 20, 2018

24 minutes ago, .justin. said:

The Calibration ID numbers won't change with any tuning that is done properly. It is the CVN, which is the first half of the checksum, that *could* change. There are 65,535 possible tune combinations that will result in the same CVN as stock for a particular calibration segment.

Ok so the cvn change is a problem? That would be where gm would see a change?

.justin. · March 20, 2018

If the CVN changes during a flash, then the ECM will store the new CVN sequentially in a history table. If there is no CVN change, then no tune history is tracked.

Crobinson16 · March 20, 2018

3 minutes ago, .justin. said:

If the CVN changes during a flash, then the ECM will store the new CVN sequentially in a history table. If there is no CVN change, then no tune history is tracked.

I see. So how does one know or does the tunner doing the programming know that the cvn will change. What I'm trying to say or get at is. If I have it tuned how can I ensure my cvn or whatever it is that gm looks at dosen't get changed and gm is able to see it, should I need power train warranty repair.

.justin. · March 20, 2018

I really can't comment publicly on that, unfortunately. The vast majority of tuners out there, 95%+, would have no way of ensuring CVN is unaltered.

Crobinson16 · March 20, 2018

Thank you , I sent you an email.

michigan2500hd · April 1, 2018

Ok just a little update on my 8 speed and it's dealership tune update.
My truck is a 2015 1500 6.2/ 8 speed with 3.42 gears with about 33,000 miles.
Took the truck in for a few things, one being a shift flare between 2nd and 3rd. And it wouldn't downshift into first during a rolling stop. ( Other items were 1.backup camera glitch.
2. dash rattle.
3. coolant leak.

Dealership said downshift delay is " normal"...
They did however verify shift flare and performed update. I asked dealer which update but they couldn't remember or didn't have record of the number. ( Strange)
After getting vehicle back a week later I could tell the truck driver differently.
Throttle response is much, much better. Not quite " cable operated" response but as good as I've experienced with " drive by wire".
I still feel a flare just not quite as bad. I want a trans that firmly and quickly bangs through the gears and not this mushy, smooth crap that's so common today.
The truck still delays shifting into first and now it's very noticeable as it kinda jolts into first at about 2 or 3 mph.
All in all I'm happier with my truck though. The throttle response and power delivery is awesome. It's like I've turned the throttle boost on my Diablosport all the way up.. Except I don't even have a tune installed, it was returned to stock before I took the truck in for service.

I sure hate taking my truck in for service because I don't like anyone touching my truck. I've worked at a dealer and know what goes on and I'm glad to have it back.
I got a new radiator and battery out of it however my truck stunk bad of dirty mechanic and oil and my oil life monitor was 35 % when I took it in and 10% when I got it back. I was told the battery was bad and truck had to be jumped but I never had any issue with the battery.
Oh well it's home now and I have it a quick cleanup. I actually enjoy driving it now due to a little better shifting, no coolant smell, no dash rattle and better performance.
I just hope the TCM doesn't "learn" and turn the shifting to crap again.

Sent from my SM-N950U using Tapatalk

Crobinson16 · April 14, 2018

On 3/20/2018 at 1:53 PM, .justin. said:

There is no way of knowing what version you have without connecting to the vehicle unfortunately. It does appear though, as you indicate, that there is an update.

If you did swap TCMs, then yes, you would be able to swap back without issue.

Just thought I would give an update, finally got to take truck to the dealer, they hooked it up and the update was available, as listed in the tis web. I asked them before I took it in and they said the same thing as you did, that wouldn't know if it was already installed or if it could be installed until they hooked it up. Drove it home and it's different different, don't know how it will truly be till I get some more miles on it and it adjust. I did notice it holds gears longer in all driving conditions. Not as much shifting between gears or possibly seems the tq converter stays locked longer but that could change after a couple miles. Good or bad I dont know yet. Also the the constant up shifting in traffic and low speeds has seemd to not be prevalent.

The Gibson · April 15, 2018

Anyone have this done? I'm wondering if this is what's need to resolve similar issues with my 6.2 8 speed.

Bulletin# 17098 - Update to address the possibility of setting false DTCs P0747, P0777, P0797, P2715, and P2724

Crobinson16 · April 15, 2018

I haven't seen that one, although if you go to the TIS WEB site that was provided you can type in your vin number and what module or controller you want to check and see what may be available. I did this for my 2018 6.2 8spd and found that there is an update available for the TCM titled "transmission update to improve shifting" . I posted a picture in my previous posts.

michigan2500hd · April 15, 2018

I just had a second update done to my 8 speed, right before my warranty expired. It shifted much better for a week or so but now it's back to it's "flare " shifting.

My question is.. Will a custom tune fix this??

I'm less than impressed with GM and the transmission tuning.