A telehandler's service manual specifies a 500-hour interval for hydraulic oil change, and an annual interval for engine oil change, whichever comes first. The telehandler has logged 400 operating hours since its last hydraulic oil change and 10 months since its last annual engine oil change. What maintenance is recommended?

Question: A telehandler's service manual specifies a 500-hour interval for hydraulic oil change, and an annual interval for engine oil change, whichever comes first. The telehandler has logged 400 operating hours since its last hydraulic oil change and 10 months since its last annual engine oil change. What maintenance is recommended?

Answer options: ✅ Change the engine oil as it's nearing the annual interval, and schedule the hydraulic oil change soon.

• Change both the engine oil and the hydraulic oil immediately.
• Only change the hydraulic oil, as its interval is operational-hour based.
• Continue operation without maintenance, as neither interval has been reached.

Correct answer: Change the engine oil as it's nearing the annual interval, and schedule the hydraulic oil change soon.

Explanation: The engine oil is approaching its annual interval (10 months out of 12), making it a priority for servicing soon, especially if the machine isn't used much. The hydraulic oil, at 400 hours out of 500, is still within its operational interval but should be scheduled for its next service. It's not necessary to change both immediately. Waiting for both intervals to be fully met risks exceeding the time-based interval for engine oil.