talking to Discount tires about going to 285 tires from stock 245. He said I would have to re-program for the Allison to read the correct speed on the speedometer. Is he correct. Also, what kind of programmer do I need, or is it too much trouble, and can it void my warranty. I have 4000 miles on my 06 2500HD 4x4. I see alot of trucks with the 285-75-R16 tires and wonder if they all re-programmed. Thanks for any info.