Speedometer Gears
Hopefully, there is some useful information on speedometer gears here for you. The identification numbers and gears on this page come directly from
1968 Shelby build sheets. Each model had a different gear based on the engine, transmission and rear axle. This combined with the standard tire size would determine
which speedometer gear would be used. This gear is called the driven gear. Ford actually adjusted the driven gears assigned to specific vehicles during the model year.

| Build Sheet ID |
Part Number |
Color Code |
Number of Teeth |
CODD-B |
CODD-17271-B |
GOLD |
18 |
C6VP-A |
C6VY-17271-A |
GRAY |
18 |
CODD-C |
CODD-17271-C |
PINK |
19 |
C6VP-B |
C6VY-17271-B |
TAN |
19 |
C4OA-A |
C4OZ-17271-A |
RED |
21 |
You might have noticed all of these speedometer gears are a solid color. They all belong to cars with automatic transmissions. These are described as "right hand" gears.

| Build Sheet ID |
Part Number |
Color Code |
Number of Teeth |
C2DA-E |
C2DZ-17271-E |
ORANGE |
16 |
C2DA-G |
C2DZ-17271-G |
PURPLE |
17 |
C4DA-A |
C4DZ-17271-A |
PINK |
19 |
C2DA-H |
C2DZ-17271-H |
BLUE |
20 |
These gears are all white with a colored tip. The color identifies the gear and the number of teeth. All of these gears belong to 4 speed cars. These gears are described as "left hand" gears.
There are probably variations of all these gears. Part numbers indicate the gears have a very wide interchange between car lines.
Changing the gears
Often times something as simple as changing your tire size will effect your speedometer readings.
If you suspect your speedometer is incorrect, perform this simple test: Time yourself on the highway. It should take you exactly 60 seconds to travel one mile at 60 mph.
If you speedometer reads incorrectly, you can change easily change the driven gear.
From under the car, remove the cable from from the side of the transmission. Increasing the number of teeth on the gear will slow your speedometer reading. Decreasing the number of teeth on the gear will make your speedometer read faster.
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