I have a 4×4 2000 ford explorer. When I put it in 4 wheel drive and turn a corner it whines really bad . I took it to 2 mechanics and they said they think it is ok. So I called the ford dealership and they said the same . What is you oppinion

The first thing that comes to mind is the outter u-joints on the front axle. There is also an inner u-joint on the right side.  Have these checked out.  They freeze up from rust and cause pressure on the front drive axle parts which can cause a whinning noise.  This is common to all 4×4s’ that use u-joints no matter what make of vehicle.