Yes, it had a lot to do with it.
I can't imagine any scenario where this makes sense. How did you come up with the MLPS causing this?
The tone ring doesn't engage anything, so how does it get a chipped tooth? Something bad is happening in the rear end is my guess.
Are any codes stored? Does the OD OFF light flash?
That should set codes.
There is NOTHING electrical or electronic that can prevent reverse. The ONLY way that can happen is if the reverse or direct clutches are damaged. And the fact that it works cold and not hot lead me to believe you have a damaged clutch.
As you found out that won't help this problem.
More signs of internal damage.
You could have done THIS, but at this point I don't think it would help.
What is way up? An unlocked converter will raise the RPM 300-800 RPM. And more than that and one of the transmission clutches is slipping.
That's very curious.
The converter clutch is working. I'd be interested to see if it kills the engine in reverse, too.
LEDs can cause the torque converter to not lock.
Not necessarily. The torque path is different (though it is still through the direct clutch) and the pressure to the clutch is higher in reverse than third gear.
And it sounds to me like a mechanical problem in the trans, not electronic.
I can only guess as to why the OD light was flashing. My guess is that the trans was overheated. Shutting the engine off with an overheated trans heat soaks the transmission, which can cause all sorts of damage. Some of it includes general weakening of parts, which can take some time until symptoms appear.
I wouldn't take this on any long trip.