Diagnose This! is a new regular feature in Truck Parts & Service. Each month we will present a real-life service scenario and provide clues as to what the ultimate diagnosis was. If you think you know the answer, be the first to e-mail [email protected] with the correct response for free Truck Parts & Service merchandise. The answer will be revealed in a future issue of the magazine.
This month’s Diagnose This! is submitted by ASE master technician and owner of Fleet Guardian, Damon Russell.
Vehicle: 2005 International 4300 rollback wrecker
Key components: DT466 engine, air brakes
Scenario: Vehicle developed a sudden moderate engine knock at all engine speeds. Noise was originating from the air compressor area. The air compressor and power steering pumps were removed from the engine and the engine was run for verification. The knock persisted.
The offending gear and the adjacent gears were changed with identically numbered parts and the repair was complete.
A close up of the failed gear.
