66-67 Dodge Charger Source Guide


Pinion Gear Chart

Posted by Al on 06/10/03
...... 24" .....26" ....28" ....30"
2.76 2538930 2538928 2538926 2538924
2.94 2538932 2538930 2538928 2538926
3.21 2538935 2538933 2838931 2838929
3.55 2538939 2538936 2538933 2538931
3.91 2538943 2538940 2538937 2538935
4.10 2538945 2538942 2538939 2538936
4.30 2538944 2538941 2538938
4.56 2538945 2538943 2538940
Please note: these numbers are for the standard style pinion gear also last two numbers are the number of teeth, 2538945 = 45 teeth

How to Calculate tire diameter: Example 265/60/15

265mm/25.4mm = 10.43 Inches Section Width

10.43 in. X 60% = 6.25 in. Side Wall thickness

6.25 in X 2 = 12.5 in Total Side wall height

12.5 " + 15" (rim Size) = 27.5" Diameter

So with this Tire size and 3.55 Gears, I would use 35 Tooth Speedometer gear.

Posted by Greg Rose on 02/17/04
Teeth Color Part Number
27 (white) 52068149
28 (blue) 52068150
29 (black) 52068151
30 (yellow) 52068152
31 (green) 52068153
32 (black) 52068154
33 (yellow) 52068155
34 (green) 52068156
35 (orange) 52068157
36 (red) 52068158
37 (white) 52068159
38 (blue) 52068060
39 (green) 52068061
40 (orange) 52068062
Posted by Dan McCormack on 02/17/04

The original 775x14 tires that came on our Chargers were about 27" in dia. With that dia. tire the number of teeth needed on the pinion gear matches the first 2 numbers of the rear end ratio. Example 3.23's need 32 teeth 4.10's need 41 teeth ect. If you have larger tires than 27" you need to reduce the number of teeth and if your tires are smaller than 27" you need to increase the number of teeth. If you tell me what size tire and what gear ratio you are running I can give you a good idea of what size pinion gear you need. There's charts in both the Year One catalog and the 66 service manual. Year One has the gears but I was also able to still order them from the Dodge dealer at least a few years ago. You also need to rotate the adaptor that goes in the tranny to match the number of teeth that your using. There's numbers marked on it that have to line up with a mark on the tranny. Directions are in the service manual