[Albery's Lawn & Tractor]

I have a '03 Dodge 3500 w/ 5.9 cummins, truck has 150K miles. Truck now seems to have no power, can't pull an empty trailer without wanting to over heat. New transmission, flushed radiator, new water pump and thermostat, no check engine light. No oil in the turbo intake. Any thoughts of what this might be?