My 2008 Silverado had a similar problem at 67K, my dealer went to bat for me & got a new shortblock. It has run great ever since, now at 99K. They can make it happen on the shortblock if you push.

 

I dont think youre truck is anything special we have seen some with 100miles to 99k miles come in for warranty engine work and we simply fix whats wrong, most common on these new trucks is camshafts and lifters that either wear out or over use oil..
You can go and complain but i think you will end up with maybe a new oil pump and bearing and gaskets.. and why worry your engine will still have another 94k miles of warranty left

 

Also if the car is in for more than a month you can request them to make your payment.