I have been looking at a 2015 Ford fiesta that has 79K miles with power shift trans. so I got online to see what I could find out about them. Oh dear, PS tranny has some problems but if trouble hasn't shown up after 79K miles should there be any worries? It is one owner and car fax is clean.
Thanks for any input on this.

Instead of a traditional fluid coupling torque converter, the PS uses to dry engagement clutch packs to facilitate engine to transmission power coupling.

One clutch engages for odd gears, and the other engages to even gears, so the transmission can shift through gears more quickly.

Dry clutches can begin to chatter/shudder when applying (and becomes pronounced due to wear and material adhering and resulting in rapid "slip/grab" and the felt effect. Once that starts, it becomes worse as the friction and steel plates become burnt/hot spotted.

The transmission can be improved to a degree with better components if a rebuild becomes necessary, but that is still going to be a cost should it become a problem if there is no coverage on a used vehicle.

Not sure if a second owner will have recourse on repairs, but I think Ford had provisions for owners to get free repairs due to class action outcome.

The Ford PowerShift is a turd. They quit making it in 2016. It may have gone this far, but that only means it's overdue. It will probably take a dump shortly after you buy it.

Every last one was defective through bad engineering.

There's worse problems than the shitty stamped metal clutch.

Thank you all for your enlightenment.