It shakes at any speed & pulsates steering wheel

Have you checked the inner and outter tie rods?Also does it ever start shaking when hitting a bump in the road?

You should be able to see both inner and outter tie rods the best way to check them is start the engine. Hold your hand on the tie rod and have someone rock the steering wheel left to right a short distance. Check both sides you should be able to fell the play in them if there bad. Do this with the wheels on the ground I just went thru this with my sisters 1999 ford expedition 4 wheel drive. Every time she hit a bump at above 40 mph the steering wheel and front end would shake. It was a bad tie rod bump steer its called.I just replaced both the left and right inner and outter tie rods on it. Let me know what you find.