Replaced the factory shocks at 156k miles. Put new nineteen 5100's all the way around and I'm not sure that it helped anything. Do the new shocks have to "break in"? Also, island if this is due to the new shocks but now when I'm on the highway it feels like the truck is "unstable". I had a 94 suburban once with 11 inches of lift and 40x17 inch tires. The way The truck feels now is very similar to the way the suburban felt. Almost as if it's swaying. Any ideas anyone?