Register now to get rid of these ads!

Strange speedometer problem

Discussion in 'The Hokey Ass Message Board' started by GinettaG12P, Dec 9, 2012.

  1. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    The speedometer in my 1958 Ranchero does not work despite my best efforts. Here is what I have done to try to rectify the problem:

    I replaced the speedometer/odometer
    I pulled out the speedometer cable and lubed it.
    I pulled the speedometer drive gear out of the transmission and inspected it
    I removed the speedometer drive gear from the cable and reinstalled it
    I drove the speedometer drive gear with my electric drill and it operated the speedometer and odometer
    I reinstalled the speedometer drive gear and cable in the transmission.
    The speedometer does not work.
    All I can figure is that the speedometer drive gear in the transmission is not engages.

    I should note that the speedometer functioned when I bought the vehicle a couple of months ago, but the I got the dreaded speedometer cable chatter. After I lubed the cable it stopped chattering for a little while and then started to chatter again. Then the speedometer quit. HELP!!
     
  2. bobwop
    Joined: Jan 13, 2008
    Posts: 6,098

    bobwop
    ALLIANCE MEMBER

    is there a clip that holds the drive gear in place?
     
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,562

    Mr48chev
    ALLIANCE MEMBER

    If you hang the end of the cable down below the dash and drive down the street does the cable turn? The other end of the cable might not be engaging the drive gear in the trans for some reason or other.

    After scrolling way way down this page http://www.transmissioncenter.net/speedometer_calibration_______va.htm are you sure you have the correct and matching speedometer gears in the trans? The driven gear may not be matching up with the drive gear.

    There is some difference between manual trans speedometer gears and automatic trans speedometer gears.
    http://www.dearbornclassics.com/tra...eter-gears-and-sensors.html?search_model_id=1
     
    Last edited: Dec 9, 2012
  4. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    The clip that holds the gear on is in place. I pulled it off and inspected the gear to see if the square socket in the gear was broached and it was not; the square end of the speedometer cable is a snug slip fit. If I pull the gear/cable out of the transmission and turn it with my drill motor, the speedometer and odometer work. The gear has a "snout" on it, but I do not see any orifice for the snout to fit into (I must admit that I did not do a thorough investigation.) For some reason, the gear in the transmission is not turning the gear on the speedometer cable.
     

  5. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    I forgot to mention that the speedometer worked with this gear when I bought the car.
     
  6. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,562

    Mr48chev
    ALLIANCE MEMBER

    Ok, first thing you need to do is make sure that the drive is turning the cable. If it isn't you have to find out why.

    Reasons why include:
    The drive gear in the the trans not turning the driven gear.
    The end of the driven gear that the speedometer cable goes in is rounded out and not turning the cable.
    The end of the cable isn't in the engaging the drive gear or the speedometer it's self.
    The cable end that goes into the drive gear is rounded off and not engaging the driven gear.
    The cable is broken or otherwise damaged.
    The top piece on a "universal" cable came loose from the cable at the speedometer end.
    You do have the cable in the housing?
    Outside of the last one those are all things I have seen causing a speedometer to not work when the speedometer is good.
     
  7. Have you ever tried loosening the collar or cap nut (not sure of correct
    term) that screws onto the speedo to hold the cable in place? On my
    Plymouth, it seems like the speedo binds if I screw that down real tight.....
    so I back it off just a little and it seems to work better.

    Just guessing here......otherwise it sounds like you have tried most
    everything I can think of. Have you replaced the actual cable (the
    inner one) to see if the result is any different. Are there any kind
    of sharp bends in the housing between dash and tranny? Hope you
    find an answer.
     
  8. 333 Half Evil
    Joined: Oct 16, 2006
    Posts: 1,440

    333 Half Evil
    Member

    Make sure that when you slip the cable into position that there is enough cable protruding to engage into the square hole in the drive gear. If you can get to the back side of the speedometer to unhook the cable there, put the cable on the transmission, then remove it from the back of the speedometer, locate the cable where you can see it while sitting in the drivers seat. Jack the car up, or dive it if you are really carefull, so you can put the car into gear and have the rear tires rolling and watch to make sure your cable is turning while the car/wheels are rolling. If it is, then reinstall the cable to the speedometer and see if it works now. If it is not turning, stop the wheels from rolling, push in on the cable while holding the housing, turn the cable while doing so until you feel it engage into the square hole in the drive gear, now get it back in gear so the wheels are rolling and see if the cable is turning now....it should be, and reinstall the cable to the speedometer.
     
  9. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    I pulled the driven gear off the end of the cable and checked to see that it was not rounded - it was not rounded, and chucking the snout of the driven gear in my drill motor allowed me to drive the speedometer, so the driven gear does, in fact, drive the cable.

    The cable is sound from square end to square end, and drives the speedometer when turned by my drill motor.

    The drive gear in the transmission cannot be turning the driven gear or the speedometer would work.
     
  10. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    The cable engages both the (driven) gear in the transmission and the speedometer. I checked this visually and by operating the speedometer by driving the driven gear with my drill motor. Everything is sound from the driven gear in the transmission to the speedometer. I have no idea why the driven gear isn't being driven.
     
  11. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    In the past and with a different car, I experienced the binding that you describe.

    There appear to be no binding bends in the cable housing, as I am able to operate the speedometer by turning the driven gear with my drill motor.
     
  12. lowsquire
    Joined: Feb 21, 2002
    Posts: 2,564

    lowsquire
    Member
    from Austin, TX

    Ive had this problem and its usually the engagement of the speedo cable into the gearbox drive. strangely the problem will be at the speedo end. there is a little brass ferrule on the inner cable at this end, and what you need to do is add a tiny washer or two so the inner cable doesnt engage as deeply in the speedo, this will leave more sticking out at the gearbox end, allowing it to engage a bit deeper into the drive gear. if you look really close at the square end of the cable at the gearbox end, i bet you will find it is ever so slightly rounded off. what happens is this doesnt quite engage and therefore doesnt spin. its often a matter of 1/8 inch or so. for some reason the inner cables are often a touch too short. bet you thats it.
     
  13. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    Thanks for the thoughts, but that is not the problem. I know this because I attached the cable to the speedometer and attached the driven gear to the cable. Then I chucked the driven gear in my drill motor and spun the driven gear. That drives the speedometer, so I know that the square ends of the cable are engaged on both ends. I'm thinking that the drive gear in the transmission has failed or has moved on its shaft.
     
  14. Mr48chev
    Joined: Dec 28, 2007
    Posts: 28,562

    Mr48chev
    ALLIANCE MEMBER

    It sounds like you answered your own question.
     
  15. Fenders
    Joined: Sep 8, 2007
    Posts: 3,922

    Fenders
    Member

    Your conclusion that the driven gear isn't being driven may be correct, but it sounds like the one thing you haven't done to double check that, is to disconnect the cable at the speedometer, drive the car, and see if the inner cable turns.

    If it does not, you are correct.
     
  16. GinettaG12P
    Joined: Sep 1, 2012
    Posts: 31

    GinettaG12P
    BANNED

    I pulled the speedometer cable/gear out of the transmission and peered in. The drive gear on the transmission output shaft looked ok, but i found that I can rotate the drive gear on the shaft just by pushing it with my finger. The drive gear is no longer attached to the output shaft.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.