Vortec 5.7 engine build

[Supercharged111]

I have Shift Lock enabled and my converter locks up immediately after the 1-2 shift and stays locked in Tow Haul. I never unlock the converter in 4th without downshifting at the same time, even not towing it is unproductive. Even the FWD 4 spd that my grandmother had in her 2003 Alero with the 3.4 I tuned. GM got a wild hair to upshift at fairly low rpm but the converter stalled over 2,500 rpm. It would go into 4th at 25 mph but would not lockup until 50 mph. It would sit at 2,500 rpm with any throttle until it hit 50 mph. I changed that one to where it would lock in 2nd gear and shift 2-3 and 3-4 while locked. The difference was almost 3 mpg better around town.

Are the locked shifts harsh? I thought I'd tried that years ago and it felt like it was going to break itself.

 

[L31MaxExpress]

Are the locked shifts harsh? I thought I'd tried that years ago and it felt like it was going to break itself.

Definately firmer! Not going to break it if it still has torque management, because GM did the same locked shifting behind the 8.1s in the Vans and 3500HDs. Not even tow haul on those, just normal WOT shifts. 75% TPS and above locks the converter around 50 mph in 2nd and keeps it locked.