New 48RE upshifting WAAAY too soon

[Yo Hoot]

It seems like when my truck is hot this happens. Happened twice in a couple of weeks.

It goes into a mode where it upshifts so early that it barks the turbo and lugs the motor. It locks into fourth and drops rpm below 1000 on a moderate to light acceleration. The first time it did this it went away on it's own. Did it again yesterday after a long highway run. I had some problems with my TST a while back... moisture in it. That was cause no start and stalling conditions. I dried it out and it seems to have fixed it.

This morning I removed the TST but I didn't drive it before I did cause I didn't want to be working on a hot motor. TST disconnected and it's shift great. I'm not sure if the TST is the issue or the trans cooled and something changes when the trans cools. I'll drive it for a while without the TST to see if it ever occurs again.

My question is, is it possible that my TST still has issues and can the TST do something to cause premature upshifting?

Second:
I had a Goerend installed. Is it possible the speed sensor or trans harness is suspect? The sensors all are removed from the old trans and re-installed on the new one.