I would simply follow the manufacturers recommendations listed in the owners manual
ENGINE BREAK-IN RECOMMENDATIONS — 3.0L
DIESEL
The diesel engine does not require a break-in period due to
its construction. Normal operation is allowed, providing
the following recommendations are followed:
• Warm up the engine before placing it under load.
• Do not operate the engine at idle for prolonged periods.
• Use the appropriate transmission gear to prevent engine
lugging.
• Observe vehicle oil pressure and temperature indicators.
• Check the coolant and oil levels frequently.
• Vary throttle position at highway speeds when carrying
or towing significant weight.
NOTE: Light duty operation such as light trailer towing or
no load operation will extend the time before the engine is
at full efficiency. Reduced fuel economy and power may be
seen at this time.