What is the oil drain interval for an Allison transmission is equipped with prognostics?

• A. 500,000 miles, (800,000 km), or every five years
• B. 50,000 miles, (80,000 km), or once a year
• C. When indicated by the gear shift display
• D. 100,000 miles, (160,000 km), or every two years

Answer: (C)

Prognostics-driven maintenance means the system watches how the oil is performing and how the transmission is being used, then estimates how much life the oil has left. It uses that data to tell you when a drain is needed. In an Allison transmission with prognostics, the maintenance action is prompted by a warning or message shown on the gear shift display. That display indicates the oil life is exhausted or near exhaustion, prompting you to drain and replace the oil.

Fixed-interval schedules (like every certain miles or every certain years) aren’t used here because they don’t reflect actual oil condition or usage. The prognostics approach aims to prevent unnecessary service and avoid oil degradation by servicing only when the system says it’s time.