John Shaw owns and operates Shaw Transport Co. During the past year, John incurred the following costs related to an 18-wheel truck:
1. Changed engine oil.
2. Installed a wind deflector on top of the cab to increase fuel efficiency.
3. Replaced fog and cab light bulbs.
4. Modified the factory-installed turbo charger with a special-order kit designed to improve engine performance.
5. Replaced a headlight that had burned out.
6. Replaced the hydraulic brake system that had begun to fail during his latest trip through the Rocky Mountains.
7. Installed a television in the sleeping compartment of the truck.
Classify each of the costs as a capital expenditure or a revenue expenditure.