Going to ask this here to see if it's a calibration issue, and going to ask elsewhere if it's a hardware issue (but hardware tips are still desired if you have any!).

I just bought a built 4L65E for my '04 Silverado SS as the stock trans was on it's way out, and I plan to build the engine and turbo it soon. So along with that I also picked up a 2400-2700RPM stall converter (https://www.summitracing.com/parts/sum-700338). I've recalibrated the transmission to match (2004 Chevy Silverado SS - PCM - Trans - v2.0 - Eng - v0.10_SD.hpt).

The issue I'm seeing is that shifts appear to occur normally, except for the 2->3 WOT shift. What's odd is that I've seen this is an issue, but it's usually that it just sits and bangs the rev limiter (due to mismatched WOT MPH and RPM targets). Mine doesn't do that, the RPM and MPH both just sorta stop climbing around 5000-5500RPM. (I will be capturing a log later) I'm not sure if this is slip or what, as the "TCC Slip" value I've monitored was around 300RPM, which I assumed was okay (since I know the converter wasn't locked) and assumed it likely isn't clutch slip, but could be wrong. A part throttle 2->3 shift is nice and firm, but harsh, so I figured a WOT 2->3 should be fine since it's commanding a higher shift pressure.

My first thoughts go to a torque reduction somewhere that is occurring and causing this to stop accelerating, but also not meet the shift criteria.

Any thoughts there?

Thanks!