LOCK THE HUBS........
The hubs are not engaged. They need to be in order for the axle to be able to turn the front wheels.
The actuator on the front differential may not be engaging to lock in the front axle. How can I fix it?
Hubs need turning on? Or maybe a fuse? If it is an automatic 4wd system (i.e. does not have manual hubs), you may need to replace the hubs. To diagnose this, jack up the front of the truck and place jack stands under both front axels so that the wheels are just off the ground. Then jack up the back of the truck so that all 4 wheels are suspended off the ground. Start the truck and put it into (forward) gear. the rear tires should be spinning. engage the 4wd system. Look underneath the truck. If the front drive shaft is spinning, but the front wheels are not turning, then you need to replace the hubs. I am told this is a pretty common problem with these trucks.
If your expedition is a 4wd have the front CV joints checked. The 4WD models have auto 4WD that sometimes lock into position and don't unlock ~ even when you don't 4WD. This have very negative effects on the front wheels when turning (especially at lower speeds on 4WD high).
In a 4-wheel drive system, the front wheels may not spin if the vehicle is in a "part-time" 4WD mode and the transfer case is not engaged or if there's a fault in the system. Additionally, if the vehicle is on a surface with low traction, power may be diverted to the rear wheels due to differential action. Some vehicles also have a "4WD" mode designed for off-road conditions that allows for uneven power distribution, which can result in the front wheels not spinning. Proper engagement and functioning of the 4WD system are crucial for all wheels to operate effectively.
If it is a full time 4wd it will not turn easily.
It uses a symmetrical 4wd design. In my opinion, it is very effective. For example, if your front wheels are on the ice, they power the back wheels and then the Subaru can keep moving. It works the reversed way as well. The only problem is, if all four wheels are on ice, then it doesn't work because even if it powers either front or back wheels, its still on ice, so it can't move.
Any of the 4WD Subaru GLs are primary front wheel drive with either mechanical or electromechanical actuation of the rear drive axle. So, in 2WD, only the front wheels drive the car.
The term 4WD wheels refers to 'four wheel drive'. It is a four wheeled vehicle that allows all four wheels to receive torque from the engine at the same time.
Put it in neutral then shift the 4WD lever in the position you want ie 4wd high range or 4wd low range, then you may have to hop out and engage the hubs at the front wheels. (follow the markings on the front of the hubs) Only use 4wd on loose surface never on bitumen, so don't forget to disengage the hubs.
When on dry pavement in 4wd the front and rear wheels are working against each other. Your forward movement is hindered by the front wheels especially in a turn, the rear wants to push you faster than the front will allow. Only use 4wd on dirt or snow.