When adusting the seat, it only moves back-and-forth on the left side. . . I looked under the seat. There is a plastic bracket that contains what looks like a speedometer cable. This apparently drives the Right side.

It has come loose from the RH track assembly. There seems to be no easy way to hook it back. Any hints?

I am not sure how this could have jumped track. I am wondering if something jambed the seat, it got really crooked and this bracket popped out. My wife drives the Durango, and said one day is was making funny noise, next day it quit moving. When I looked under seat the only thing there was an ice-scraper. Seems unlikely it jumped up and jambed the seat.

Taking it in for warranty is a pain for me, (blows half a day of my time), but I might have to take it in if I can not fix myself.

 

Sounds like the ice scraper got caught in the path and caused the issue. Be sure nothing is under the seat when you take it in!