The info below is from the "Owners Manual" in my 2014 Explorer.
Your vehicle may tow a Class I or III trailer provided the maximum trailer
weight is less than or equal to the maximum trailer weight listed for your
vehicle configuration on the following chart.
Engine and trailer class
Maximum GCWR Maximum trailer weight
Front-wheel drive vehicles
2.0L GTDI, Class I 6880 lb (3120 kg) 2000 lb (907 kg)
3.5L TiVCT, Class I 6940 lb (3147 kg) 2000 lb (907 kg)
3.5L TiVCT, Class III 9980 lb (4526 kg) 5000 lb (2268 kg)*
Four-wheel drive vehicles
3.5L TiVCT, Class I 7110 lb (3224 kg) 2000 lb (907 kg)
3.5L GTDI, Class I 7400 lb (3356 kg) 2000 lb (907 kg)
3.5L TiVCT, Class III 10160 lb (4608 kg) 5000 lb (2268 kg)
3.5L GTDI, Class III 10400 lb (4717 kg) 5000 lb (2268 kg)
*For towing trailers up to 3500 pounds (1588 kilograms), use a
weight-carrying hitch and ball, which uniformly spreads the trailer
tongue loads through your vehicle’s underbody structure. For towing
trailers over 3500 pounds (1588 kilograms), up to the maximum trailer
weight, we recommend you use a weight-distributing hitch to increase
front axle load while towing.