Many late model trucks have variable geometry turbos. The variable geometry allows for OEMs to meet emmisions standards and provide a flatter torque curve allowing for better performance over a larger RPM range.
The old turbo failed due to carbon build up. The excess carbon prevented the turbo actuator operation. Both turbo and actuator had to be replaced.
This failure was preventable with proper preventive maintenance. Check out how we can help prevent this type of failure here