Really Hard WOT Shift - 2012 Silverado 6L80e

[rblloyd]

So to provide some background, I have owned my i1000 for a while now and it is fully updated. I had it paired to my previous 2008 Silverado with a 4l80e. Worked great, loved the way it woke the truck up. It was tuned with the 87 Octane tune with firm shifts. I recently bought my father's 2012 Silverado with the 5.3L 6l80e. Also a good truck, but for the past little while I have been trying to solve an issue related to shift firmness and the i1000.

After tuning the truck with the 87 Octane tune and firm shifts, it once again woke the truck up. I love the around town performance and shifting, but at WOT the thing shifts so hard that it spins the tires 1-2 and tries 2-3. It is extremely jolting and unpleasant. I love the feel of firm shifts around town. but at WOT with a stock drivetrain, this is sure to break something. So, I decided to do some testing. I lowered shift pressures in all gears at WOT to -20 and made sure that TM was still enabled. No change. So I reflashed the TCM tune to the stock tune with the 87 Octane ECM tune. No change. Long story short, I have tried just about every combination of TCM tune and they all shift super hard at WOT, until I tried the firm shift tune with the stock ECM tune. Other than the loss in performance, the shift on the truck was perfect. WOT shifts were smooth, but the around town shifts were still sharp and crisp.

So, long story short, is it possible that the Diablo ECM tunes are not pulling timing or something like that before a WOT shift? Can this be updated so that I can enjoy the performance advantage of the 87 octane tune with firms shifts without breaking my neck? I have gotten used to this and usually let out before a shift when passing someone, but when others drive my truck it is an awful feeling.

Sure would appreciate any help. Thanks in advance!

[mikel]

Please load the pcm and tcm tune you prefer to use and then post the backup and last tune written files for pcm and tcm here and we'll sort it out.

[rblloyd]

Thanks Mike, sure appreciate it! See attached. This is the 87 Octane tune with a few simple modifications. TCM is the firm shift tune with no modifications.

[mikel]

load this one....should be better.

[rblloyd]

Hi Mike. No go on this tune. I got it installed ok, but it may even be worse than the canned tune. I think I spun the tires slightly during the 2-3 shift. Thanks in advance for your help.

[mikel]

worse how?

We reenabled all the torque reduction for shifting...are you running this with the tcm tune or no?

[rblloyd]

I can try it again, I installed it with the firm shift TCM with no modifications. Should I try it with the stock TCM tune?

[rblloyd]

Mike,

I spent some time this weekend to reload the stock TCM tune to the truck without modifying any settings. I also reloaded the custom tune you sent to my ECM. I shouldn't have said that your tune shifts worse because that is not true, but it is feels much the same as the canned tunes. Still pretty violent.

I was hoping the changes that you made would fix the issue. Any other ideas you might have? I know its crazy, but the stock ECM tune shifts extremely smooth at WOT regardless of what TCM tune I have loaded. It makes me wonder what special config they used to accomplish that?

Thanks!