As far as closed loop goes, I'll check tonight.
I also think that it should throw a code if there is a discrepancy between realized ratios and selected gear. I think that's odd, but can't figure out why. Is there a known issue with shift solenoids clicking but not engaging?
Prioritize drivability symptoms themselves over codes as it doesn't really matter if they set/store or not if you're having a problem...They can be helpful with the diagnosis or not but don't get hung up on lack of DTCs plus the PCM can only place so many sensors/switches for monitoring purposes. Solenoids can fail in two ways: Electrically or mechanically...If they fail electrically, it will throw a code (voltage, continuity, performance, stuck on/off) but if the diaphragm fails a code may or may not be set.
That said, a no-upshift condition is almost always command and control which means PCM, harness, solenoids, valve body. So if your scan tool is showing the PCM commanding the 3-4 upshift (
but it physically stays in third; it never upshifts to 4th gear then neutrals) then the communication is going to the transmission and the health of the OD clutch pack cannot be assessed as it's not being commanded 'on' either electronically or mechanically. And since you have normal up and downshifting from first through third gear (right?) then I'd also rule out shift solenoids, harness, etc as potential causes (though you can always test with a multi-meter just to be sure).
Here's a 4L80E apply chart to help you know what should be working in a given gear and determine the source of the issue. Based on what you've described thus far, I think it's valve body but obviously, could be wrong.
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