7. GM redesigned the idler arm on the '99-and-up Silverado/Sierra to be stronger and last longer. In order to support the drop-down steering truss that Pro-Comp uses to correct the steering geometry, two new greasable rod end links are incorporated into the front lower subframe. These two links act as additional idler arms and share the stresses exerted by big tires and off-roading on the pitman arm and factory idler arm. It helps to have small hands if you are going to make these modifications to the steering with the front differential in the truck.