Announcement

Collapse
No announcement yet.

Speedometer pinion gear

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Speedometer pinion gear

    I have a 1950 Champion. I think I need to change the pinion gear for the speedo. How can I tell what rear end ratio I have on the car?

    Also, is it difficult to change?

    Thanks all



    Harry

  • #2
    There should be a tag under one of the screws holding the rear cover to the differential housing that has two numbers on it. Divide one number by the other and that will give you the gear ratio. You can also turn a wheel and watch the drive shaft. The drive shaft will turn 3 to 4 times for every revolution if the wheel. If all of that fails, you can remove the differential cover and the number will be stamped on the edge of the ring gear. Bud

    Comment


    • #3
      To add to Bud's response: put a piece of tape or a chalk mark on the driveshaft so you can tell exactly how many times it turns for each revolution of a rear tire. Fractions are important.

      Skip Lackie
      Washington DC
      Skip Lackie

      Comment


      • #4
        Harry; it is a slam dunk to change! You first of all have a cork or suitable material GASKET handy to replace under the speedo cable -Trans. end. Then unscrew the screw holding the clamp to the Trans. and pull it out. Pull the Pinion gear off of the cable end, push the new one on, replace the gasket with some gasket sealer on it, re-insert the cable, tighten the clamp.

        Most Studes. are due for a cable lubrication job which is done from INSIDE the car at the Speedo end of the cable per the Shop manual.

        Doing this first before changing the gear and hand spinning the speedo head to check for a seizure there MAY save wasting another Pinion Gear, as those two factors are often the cause of pinion failure. [:0]

        StudeRich
        StudeRich
        Second Generation Stude Driver,
        Proud '54 Starliner Owner

        Comment


        • #5
          Thanks! The tag on the differential housing states: 4 1 over a 9. I assume that means a 4:1 ratio...

          Harry

          Comment


          • #6
            41 divided by 9 =4.55 to 1 ratio

            quote:Originally posted by elerslie

            Thanks! The tag on the differential housing states: 4 1 over a 9. I assume that means a 4:1 ratio...

            Harry
            Frank van Doorn
            Omaha, Ne.
            1962 GT Hawk 289 4 speed
            1941 Champion streetrod, R-2 Powered, GM 200-4R trans.
            1952 V-8 232 Commander State "Starliner" hardtop OD

            Comment


            • #7
              Ok, thanks. Only one final issue. The parts manual only lists a pinion for a 4.56 ratio with OD. I assume that's the one.

              Harry

              Comment


              • #8
                Thats the one you want because when you divide the two numbers it comes out to 4.5555555.to 1


                quote:Originally posted by elerslie

                Ok, thanks. Only one final issue. The parts manual only lists a pinion for a 4.56 ratio with OD. I assume that's the one.

                Harry
                Frank van Doorn
                Omaha, Ne.
                1962 GT Hawk 289 4 speed
                1941 Champion streetrod, R-2 Powered, GM 200-4R trans.
                1952 V-8 232 Commander State "Starliner" hardtop OD

                Comment


                • #9
                  Thanks!

                  Divide numbers to determine ration vs. just saying it. So Studebaker!

                  Merry Christmas!



                  Harry

                  Comment


                  • #10
                    quote:Originally posted by elerslie

                    Thanks!Divide numbers to determine ration vs. just saying it. So Studebaker!
                    Actually it isn't! Other makes (many) that used the same Dana Spicer Rear axle in the same time frame would have said the same thing, because that is the actual number of teeth on the Ring Gear vs the Pinion Gear teeth.

                    In later years Dana used both, and later still, just the ratio.

                    StudeRich
                    StudeRich
                    Second Generation Stude Driver,
                    Proud '54 Starliner Owner

                    Comment


                    • #11
                      Dear Stude Gods,

                      Ok so I got a new core and and new pinion gear. Installed same. Twisted gear and speedo end turned. Drove about 35 feet and heard a click. No register.

                      Took pinion gear out and core had sheered at the pinion gear.

                      Is the problem on the gauge end?

                      Harry

                      Comment


                      • #12
                        is this what happened to the previous gear ???

                        Comment


                        • #13
                          Yes, I think so.

                          Harry

                          Comment


                          • #14
                            Could you have too sharp a bend in the cable, or a pinched cable housing etc. ?

                            StudeRich
                            StudeRich
                            Second Generation Stude Driver,
                            Proud '54 Starliner Owner

                            Comment


                            • #15
                              I was going to suggest a routing issue myself....Service bulletins identify early 59' Larks as having "soft" gear on the tranny shaft. I believe they were "recalled" retrofitted with better gears....I installed NOS core and gear in this 63' Cruiser of mine a year or two ago....unfortunately, when I was re-installing the front X-member one of the mounting bolts crimped the core housing and snapped the gear......couldn't see it above the frame lip from underneath til the deed was done....Short of a crimp or sharp bend, your tranny gear might be suspect.....Its hard to see from under the car, and looks can be deceiving. My 59' gear(tranny) was stripped, but with a mirror and good lighting it didn't look damaged at all. Might have to pull the rear casing off and get a better look....I'd go that route before I continued killing $30. gears.....

                              Comment

                              Working...
                              X