I am servicing a couple that have over 300,000 miles. One has 389,500 miles on and we just did balljoints and steering gear. It won't be 3 years old till November 15,2005. The other one belongs to a Cummins service manager who hotshots on the side, he has 305,789 miles on since March 28,2003 . We do his engine diagnostics since Cummins cannot scan it. We also do his suspension and brake work.