Hey Steve, I'm working on a 2014 Sierra 4x4 5.3 with a LT4 blower. Just got the truck back from our local tuner and it made 485 rwhp on 9psi with E85. And of course now there is the fine tuning of the good ol' 6l80. Looking back through the tune all of the tcc lockup tables are mostly stock meaning that its locking at WOT as a stock one would. I was under the impression that when making higher horsepower (especially in a heavy truck) on a stock converter and stock trans that you would want the converter unlocked under WOT? Especially through the shifts. Also under normal driving the converter shudders upon lockup after the 2-3 shift is made. All other gears and lockup seem to be ok. I'll post the tune up when i get home tonight. Thanks for your help.