Steering Gear Box problems of the 1999 GMC Sierra 2500

This vehicle has been in the repair shop at the dealer listed 7 different times for a continual problem with the truck pulling to the left side. It has been aligned numerous times, tires changed, steering box controller replaced, sensors replaced, etc. We still have this safety problem with this truck. We now have contacted GMC about all these problems. Since the truck is a company vehicle we can not get a replacement or refund under the lemon law. Except the applied warranty law? we would like to see the problem with it pulling left and now banging every so often when put in gear. We were informed GMC put in a new system in all there pickup trucks steering assy. S that are supposed to allow the truck to drive as smooth as a car. We feel this is the main component that keeps acting up causing these problems. If we cant get this truck repaired right once and for all we are going to take legal action to either have this truck replaced with a even trade or full refund and damages with possible. Thank you for any assistance you can give.