Originally Posted by L99BEN
I had my gears swapped on my 12' 5.0 with the speedo calibrated at the dealer and no effect on warranty. If I calibrated on my own using an SCT tuner for example, they may have had an issue with that since it involved a reflash.
I don't see how calibrating your a speedo would have an effect on your powertrain especially with a device specifically designed to calibrate the speedo only.
Like I said, go talk to your local dealership, there are a few that are more lenient than others on this subject. Maybe Ford had a different policy? I just know I've heard it on here many, many times....ANY change to the factory settings on the ECM is an automatic void of the powertrain warranty in most cases. Call up your service manager at your dealership......and let us know what he says.