Tune effectiveness? 6.2 - 8 speed

[wlezel]

2017 GMC Sierra 6.2 - 8 Speed tranny

Just out of curiosity, how much of a difference does an engine tune make since the transmission isn't tuneable? I'd imagine a engine AND tranny tune would give quite a bit better results (I really wish it was possible) than only being able to tune the engine alone on the 2017/2018 8 speed trannies.

Does just tuning the engine alone make that big of a difference since the shift points can't be tuned?

I've been running the Diablo tune for a while now and have been since like 250 miles on my truck, so I don't even remember what it felt like before. lol. Just curious what everyone thinks, especially if someone else has the same truck with the untuneable transmission.

Thanks!

[mikel]

theres a little TM in the trans that will always be there, but its less of an issue at stock power levels than if you start making more power.
Obviously being able to firm up the shifts and speed them up a bit is beneficial when possible.

[wlezel]

Hey Mikel, I know they are not released yet so you probably have no idea, but the new 2019 GMC Sierra/Silverado is doing away with the 6 speed trannies and going to an 8 speed (I'm assuming same one I have) and offering a new 10 speed option as well.

Do you know or expect the new 8/10 speeds in the 2019 models to be tuneable? It would be weird for GM to lock out the trannies in 2017/2018 then make them tuneable again in 2019+

Thanks for the feedback!

[mikel]

No, none of the 17+ 8 or 10 speeds (T87a TCM controller) are supported for tuning unfortunately.