Ring and Pinion change on 2008 Ford F-350 Super Duty

Who has successfully changed out differential gear to higher gear? I want to go from 4.30 to 3.73 gear ratio to improve fuel economy since I am no longer planning to haul heavy 5th wheel.

Asked by for the 2008 Ford F-350 Super Duty
If is 4x4 then will need to do both axles. This is a big job and best left to experts. This is nothing you want to get into if have no experience