2007 chevy silverado steering shudder over bumps

Are the wheel lug nuts tight? Jack up the front end and wiggle each wheel to check for loose wheel bearings. If the truck has a lot of miles, the upper and especially the lower ball joints may be worn enough to cause problems. With the wheels back on the ground, have someone rock the steering wheel back and forth slowly while you watch each tie rod end for looseness. If the left wheel moves before the right one does, there is play somewhere in the linkage between the wheels.