View Full Version : Project A: Changing Speedometer Pinion

10-05-2006, 11:54 AM
I have an apparent conflict between the Studebaker Parts Manual and some vendors. As you have seen from other postings, I need help!

Here is the question:
I am changing my differential to 3.07 (another thread on that one), and need to change the transmission/speedo interface to match. The parts manual drawing seems to imply that ALL these are needed, True?/False?

1556040 3.07 pinion 16 teeth
1544875 Gasket, speedo, drive pinion lock plate
1552794 3.07 gear, speedo, 7 teeth


Terry, North Texas
1963 Avanti R2, 63SR1065
(in stage 1 resto "Project A")
1985 Kubota L2202(Diesel)
2000 VW Jetta GLS
1999 Toyota rice burner

10-05-2006, 07:48 PM
This may very well be the case. If you look at the parts manual, you'll find that one "gear" may be used with a multiple #s of "pinions". Your axle ratio may dictate the use of a different gear. These are pressed onto the tail shaft inside the tranny. On the Avanti you would have to remove the tranny in order to remove the tail housing ..WAY to much trouble AND expence:(. Your best way out...look in the yellow pages for the local speedometer shop. They have the ability to make a small gear reduction unit that goes inbetween the cable and the tranny to correct this error. The last one I had done was about $50.:) Even if it was a C-note, that would still be cheaper than the alternative.;)
Hope this helps.
Dan Miller

Road Racers turn left AND right.

10-05-2006, 08:15 PM
Cheapest way to get around an inaccurate speedo? Just know the error!;)
Both my Impala and my Camaro are 5 mph off fast, so indicated 70 is
actually 65. The Avanti seems to be about 10 to 15, though I havent
used a "check point" yet to see!

The Impala was calibrated when it was a police car, with 15" wheels.
I got the correct 17" Impala SS wheels for the cloning, & the speedo
is off now. The Camaro was a similar issue, went from 16 inch Z28
wheels to 17 inch SS wheels.


'63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: 97 Z28 T-56 6-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires