Duty cycle Ford V-10 (( update bottom post))

I was hoping for a long trouble free life on my work truck, a 2013 Ford F550 with the 3 valve per cylinder V10. We bought it new last April and it just turned 133,000 miles! Unfortunately it just suddenly last week developed a nasty tapping noise from the upper passenger site of the motor. I have a feeling it's a valve lifter, but boss hasn't yet taken it anywhere, nor have we pulled the valve cover to take a look. I'm disappointed because this truck has recieved fresh Motorcraft semi-synthetic oil every month since new. I hope this is an isolated insident