6.2-6sp shifting issues

[ChrisNJ]

New here, glad I found it. Have a 07-Sierra Denali that is either a race car or a dog, no inbetween. Upshifts way to early, then requires a lot of pedal to get it to downshift. The interesting part is that my wifes new Yukon XL Denali with same drivetrain does not have this problem. Her's upshifts early as well, but comes out of it quickly, easily, and seamlessly, getting the truck moving again. Seems like the solution is simple, with just a shift pattern change. Any products to help? I don't think I need any engine mods, as it has plenty of power.

[wait4me]

v2 is what you need to modify your trans

[Maggie]

v2 is what you need to modify your trans

Are the 6lxxE calibration files available now?

[Jared Duramax]

i got the same problem but with a yukon denali short and it is like a gas guzzling 4 banger i need to do something with it

[ChrisNJ]

A TSB came out in Oct-Nov. Once installed the shifting issues are much better. Still not great, but acceptable now.

[Jared Duramax]

but when its below 70 out the truck runs like a raped ape but above 70 its a gas guzzling 4 banger so im thinking it has to do with a temperature sensor or timing tables with different temp settings ive had all the TSB updated on it and they all make it worse that originally