ok so i have ruled my speedometer problums down to the gear in the extension housing.
i belive my 77 f350 has a 4 speed with 1st being a very low gear, which ever it is called. I jacked up the truck and spun the drivshaft and found the gear in the extension house to be egg shaped and missing a chunk.
so does any one have a picture of this gear. or the part numbers for it.
Were would the id tag be on the tranny I cant seem to find the one on mine.