Steering wheel has become stiff Explorer 1999
 

What can cause the steering wheel to become stiff. It is on a XLT Explorer with a SHOC engine. It turn 1/4 then 1/4 rotation gets gritty or stiff, both left and right turns.
I have changed the belt tensioner, tensioner pulley, serp. belt, ball joints are good, no visible damage on the front side.
There is a visible tear on the steering shaft about one feet below the top radiator hose for many years now. I sprayed some WD 40 but probably not enough.
The fact it goes through a puddle of mud every morning and evening for about two month now since it is the rainy season now.

Make sure the u joint on the input shaft is not the problem.

Thanks Hanky, I took it to the garage, since my fixes did not work. Will ask him to check on the same ....