2004 4x2 currently with around 250k miles. I've had no real mechanical issues with the truck. I have replaced some wear items. 1. Brake pads and rotors. 2. Ball joints, upper and lower control arm bushings, outer tie rods. sway bar bushings and links, and shocks. 3. rear differential speed sensor. 4. Body bushings, but only B and C position, A and D are still fine. 5. Oil and filter change every 3-5k miles. 6. Transmission fluid and filter. 7. Rear differential fluid change 8. Valve cover gaskets, and oil pan gasket 9. The truck has had three alternators on it over the years. 9. Instrument cluster** this went nuts around 200k miles.-->so I guess this is my only BIG mechanical failure. I've done all the work myself, so, maybe $1200-$1500 parts total over the years. Not including tires and batteries, the last set cost me roughly $800 about a month ago. Other than those items its really mostly just been fluid changes and wear items. Oil, transmission, rear differential, and filters. The engine and transmission run as good today as they did when new. It's really been a problem-free truck.