[Mondaveo]

You're talking about the Powershift which is the Ford name for a range of automatic dual-clutch transmissions made by Getrag.

Fiesta and (petrol) Focus used what's known as a 'dry' clutch set-up. These were the Powershift units that became notorious for multiple failure modes due to overheating, contamination on the clutch plates and failures of the electronics.

Mondeo (and diesel Focus) used a 'wet' clutch variant, where the clutches are continuously bathed in fluid. This design was mostly immune to the problems experienced with the dry clutch versions, and is generally reliable apart from some proportion having electronics issues (my own car falls into this category - experienced a faulty sensor which made the gearbox perform less than optimally). The caveat is the gearbox requires the fluid to be changed at 5yr/60,000km intervals, and this is pricey but it is absolutely imperative you adhere to the service schedule.

For the model years you specify, the Powershift gearbox was fitted to Mondeos with either the Ecoboost 2.0L turbo petrol engine and the Duratorq 2.0L turbo diesel engine. There was a third 'base' engine option appearing in the cheapest LX grade, the Duratec 2.3L NA petrol, which actually uses a conventional torque-converter automatic gearbox made by Aisin.

As a point of detail, the Mondeo wagon only came with a petrol engine in the base LX trim, being the 2.3L NA with torque converter. Otherwise, your only choice with the wagon was the diesel. The 2.3 + torque converter combo is reliable and has no known issues, but it is also the least dynamic option.

By and large, the Mondeo with wet-clutch Powershift is reliable. It just gets a bad rap due to sharing the name with the truly flawed dry-clutch units. This can work to your favour when buying second-hand. That said they can sometimes still go wrong, and problems tend to be expensive to fix. But if you look out for the two or three typical issues, and keep the maintenance up then they are usually perfectly dependable (and drive pretty well too).