Correcting Speedo on 91 f-350
Ok so I bit the bullet and bought a 91 350 diesel, felt like while driving down the road the speed was off, got out the GPS and confirmed I am reading 10 mph over what I am actually doing. is this a simple gear to swap out like in jeeps? if so anyone got a link to which gear I need with tire size? if not what's it gonna take to make this thing read correct?