Late 6L90 changes, no Desired shift time or inertial adder? GM Updates?

Hey Guys,

I have an '08 Suburban 2500 (LY6/6L90) that frankly, I hate, hate, the way this thing shifts. Stock was awful, horrible. I am not good with A6's and its still awful and horrible just a little less gooey. I have a 2017 Isuzu NPR HD with the same combo (Both E38/T43) that frankly, drives really nice. Shifts are crisp, smooth and without hesitation so I pulled the tune hoping to learn something, but I see it has no desired shift times, no inertia adder, no output torque multiplier etc.

1st.) So does anyone know about the history of the 6L90 tuning, like is the Isuzu missing these tables because its a commercil truck and not as "fancy" or did GM get rid of those tables because the transmission was too confused for its own good and shifted like crap?

2nd.) Anyone know if I can apply these changes to my 2008 with a Tech II? Or was there a hardware change?

There are a lot of differences between the 2007-2009 calibrations and the 2010+ calibrations.

You just need to know what to look for and how they function.

2010+ do not use desired shift time, everything for shift time is controlled by the Shift time torque adder normal upshift tables.

The pre 2010 calibrations used that as well but under medium to heavy throttle the values are likely to show 0.0000 but will have a value at low to negative torque values.

You can make your 2008 truck shift better, it just takes different steps. Look more into shift pressure changes and on-coming pressure preset changes to make it do what you want. I also disable the torque converter lock up on the first few gears and change the shift mph speeds so it won't shift into 5th and 6th gear at like 40mph.

Quote:

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Originally Posted by 5FDP

There are a lot of differences between the 2007-2009 calibrations and the 2010+ calibrations.

You just need to know what to look for and how they function.

2010+ do not use desired shift time, everything for shift time is controlled by the Shift time torque adder normal upshift tables.

The pre 2010 calibrations used that as well but under medium to heavy throttle the values are likely to show 0.0000 but will have a value at low to negative torque values.

You can make your 2008 truck shift better, it just takes different steps. Look more into shift pressure changes and on-coming pressure preset changes to make it do what you want. I also disable the torque converter lock up on the first few gears and change the shift mph speeds so it won't shift into 5th and 6th gear at like 40mph.

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Thanks for the input, I guess I have been a little confused because I have read about 08/09 differences, but I also have a 2011 Suburban 2500 and it still has (uses?) the desired shift times, inertia adder, multipliers etc.

Maybe it's something specific to that type of vehicle.

All of the files I have from 2010, 2011, 2012 and 2016 for the 6L80/90e don't have that desired shift time section. These are in the pickup trucks and not SUV's.

I'm kinda curious what the 2500 file looks like, post them up if you want.

Quote:

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Originally Posted by 5FDP

Maybe it's something specific to that type of vehicle.

All of the files I have from 2010, 2011, 2012 and 2016 for the 6L80/90e don't have that desired shift time section. These are in the pickup trucks and not SUV's.

I'm kinda curious what the 2500 file looks like, post them up if you want.

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I will say the 2500 Suburban's always seem to have oddities about them. They tend to get a lot of leftovers and hand-me-downs since they were low production, I guess.

Attached are the stock tunes from the 2008 and 2011.

I wish the repository worked, would love to have more vehicles to browse and be able to upload.

Seems odd that the 2011 file even shows half those tables, they are just full of zero's expect for the skip shifts like 1-3 etc etc. It's still using the torque adder tables for all the other normal gear changes.

I'd say monkey with the torque adder table on the 2008 file for part throttle stuff and then just go at it with the shift pressure and on-coming pressure presets. Those few changes should make it shift way better.