I have a ford Explorer 2005 with new ball joints (top and bottom), a new drive shaft (I think there are 2 driveshafts but apparently the other one is still good), and new front and back brakes. I have a strong vibration in the steering wheel at 55mph. What is your opinion on the problem?
If you take your truck to the mechanic, tell him to check the wheel balance on the front and rear tires.
When the mechanic has the tires on the wheel balancer he can check not only the wheel balance but also the tread of the tire and the condition of the rim.
He can make sure there are not any broken belts in the tire causing a bubble in the tire or a bent rim. All three of these conditions can cause a vibration.
These suggestions are for a front end vibration. If these suggestions don't work then the vibration will have to be further diagnosed.