A fifth-generation Explorer with an expensive engine-and-driveline to-do list — buyable only with the water-pump, PTU, and recall history in hand.

On all-wheel-drive cars the Power Transfer Unit — the gearbox that sends power to the rear axle, sitting beneath the exhaust — leaks oil from its pinion seal at low mileage. A gen-5 shop mechanic: 'I probably replaced over 20 PTUs; they all pretty much leak.' The fluid is sealed for life from the factory, so once it starts leaking the fluid overheats, vents, and the unit fails internally; the fix is roughly six hours of labor. The prevention mechanics recommend is changing that sealed fluid every 15,000-20,000 miles with a new drain plug. On an AWD 2016, look underneath for oil weeping around the PTU and ask whether the fluid has ever been serviced.

The gen-5 Explorer's best-known concern is exhaust odor — sometimes measurable carbon monoxide — reaching the cabin. A mechanic explains that in cases with no oil leak, 'the exhaust fumes from the rear exhaust get inside the cabin.' Ford created a CSP — a Customer Support Program, the industry's quiet extended-coverage — numbered 19N05, covering 2011-2017 Explorers for this concern. If you smell exhaust inside, especially with the climate system on recirculate-off and the tailgate area, ask whether 19N05 work was performed and verify the exact coverage terms in the bulletin.

The gen-5 automatic draws complaints of harsh jolts, slipping, and 'won't go into drive.' Ford runs Customer Support Program 20N07/20B27 for 2016-2019 Explorers with the 2.3L engine, extending transmission coverage and adding a powertrain-control-module reflash for the torque converter — with a further 12-month torque-converter warranty from the date of that reflash. On the V6 cars the coverage is thinner. On a test drive, feel for slip or a shudder that a dealer reflash can't cure, and on a 2.3L car ask whether the 20N07/20B27 work was done.

Two safety recalls dominate the recent complaint sample. The rear suspension toe link can corrode and fracture in road-salt states — a loss-of-control risk — under a chain of expanding recalls (19V-435, then 20V-675 and 21V-537 for salt-belt cars). And the A-pillar trim (24V-031) and B-pillar door trim (25V-347) can detach while driving; the recent complaint file is full of owners who report the trim flying off at highway speed and then waiting a year or more for parts. All are free repairs — the catch is availability. Verify by VIN which are open and whether parts have arrived.