Hydramatic Speedometer Gear

ratlee2 Expert Adviser
Years ago I had Gus Souza rebuild the Hydramatic transmission for my Dad's '53 Hornet.  I had not yet pulled the drivetrain out of the Hornet at the time, so I sent out the spare dual range transmission from our '52 parts car.  I recently put the car back on the road for the first time on over 20 years and discovered my mistake.  Apparently, the spare transmission came from the 3.58 axle ratio car and now the speedometer is 10 miles per hour higher at 55mph.  I still have the original transmission, so my question is how hard is it to swap out the speedometer gears?  Do I need to pull the tail shaft housing to do it?  I find no information on it in the '52 shop manual or Hydramatic manual.  Also, here is a picture of the car.  So far so good.  No parts have fallen off over the last couple days of driving it.


  • Glowplug
    Glowplug Expert Adviser
    edited October 2023
    The speedometer drive gear is behind the speedometer cable, pull it out and put the appropriate equipment in place to achieve the correct speedometer readings.  See the attached chart. Nice looking Stepdown, enjoy.  Ken Cates
  • ratlee2
    ratlee2 Expert Adviser
    Thanks Ken.  I was hoping I only needed to remove the outer gear and not have to remove the tail housing.