1998 Chevrolet Silverado steering problems

Dt*: the contact stated while making a slight turn in a curve, the steering wheel jerked making a sharper turn. This began in september 2005 and the dealership was unable to determine a problem. This progressively worsened. While driving 55 MPH, down a mountain, the steering wheel jerked causing the vehicle to hit a rock wall and the vehicle spun out of control. There was a police report taken at the scene. The vehicle was towed to a salvage yard, where the insurance company deemed the vehicle totaled.

1998 chevrolet silverado (k1500) - the tension required to turn the steering wheel momentarily becomes very loose while making right-hand turns. Driver gets the sensation there is no control of the vehicle during this time. Dealer says there is no recall but the mechanic at the same dealership told me that he has replaced hundreds of "steering wheel speed sensors". I had no choice but to fork out $200 to have it replaced. Seems to be ok now, but for how long? *nlm