2004 f250 SEIZED MOTOR.

2004 F250 4X4 6.0 DIESAL 64000 MILES. Left To Store Today And Truck Started To Knock In The Motor. I Shut It Off After Pulling Over. I Checked Under The Hood For Something Obvious With No Findings. I Started It Again With The Same Problem(SOUNDED LIKE THE TURBO LET LOOSE), Shut It Down. I Had It Towed To Ford And They Called Me Saying The Motor Is Seized. They Asked For Permission To Tear It Down To Find The Problem At The Tune Of $2800. I Told Them To Continue Based On The Fact It Is Under Factory Warranty. The Only Trouble Im Having Is That I'm The Second Owner (10mo.) And Have Not Done Anything To The Truck. What Happens If Someone Before Me Has Done Something To The Motor. (ie:chips, Parts Etc...)
I Don't Need A $10,000 Bill From A Dealer Who Blames It On Me...
Any Suggestions