Locks when it shouldn't

[Matt]

Next, I tried unplugging the front and rear ELSD cables from the diffs. Still no change.

This is the troubling part.... if you've unplugged the solenoids the diffs should be open and remedy your issues. Makes me wonder if its more of a t-case issue. Even with open diffs, if your t-case clutches are engaging you'll get driveline binding. Either way it sounds like more of a mechanical issue than a bad sensor since you're not throwing codes.

I know you're usually on top of your game with this stuff.... but when was the last time you replaced all the driveline fluids? And did you add the additive to the diffs?