Hi this is Macksmom's husband

I have been a GMC mechanic for years...got bored tonight so logged in here
If you have a 2500HD with an
allison transmission, you CANNOT change the parameters, it's a software issue with the tansmission programming.
Other transmissions can be set up to accomodate different tire sizes although you may be charged.
It will not be covered under warranty because you are making changes to the factory settings of the truck.