Here is some info I saved long ago that may help you
You need to determine what size tire you will use on each rim size. You can get 28" tall or 26" tall on both the 14" and on the 15" rims. on 15's, 235-60-15's are about 26" tall, and 275-60-15's are 28".
DODGE PLYMOUTH CHRYSLER MOPAR SPEEDOMETER PINION GEAR CHART
Axle Ratio Rear Tire Diameter
24" 25" 26" 27" 28" 29" 30" 31" 32" 33"
2.76 30 29 28 27 26 25 24 * * *
teeth teeth teeth teeth teeth teeth teeth
2.94 32 31 30 29 28 27 26 25 24 *
teeth teeth teeth teeth teeth teeth teeth teeth teeth
3.23 35 34 33 32 31 30 29 28 27 26
teeth teeth teeth teeth teeth teeth teeth teeth teeth teeth
3.55 39 38-37 36 34 33 32 31 30 29 28
teeth teeth teeth teeth teeth teeth teeth teeth teeth teeth
3.91 43 42-41 40 38 37 36 35 34 33 32
teeth teeth teeth teeth teeth teeth teeth teeth teeth teeth
4.10 45 44-43 42 40 39 37 36 35 34 33
teeth teeth teeth teeth teeth teeth teeth teeth teeth teeth
4.30 * * 44 43-42 41 39 38 37 36 35
teeth teeth teeth teeth teeth teeth teeth teeth
4.56 * * * 45 43 42-41 40 38 37 36
teeth teeth teeth teeth teeth teeth teeth
* not available.
Automatic Trans.
Speedometer pinion #'s
Speedometer pinion #'s Superceded
I was using the Speedo pinion chart in the Moparts garage. Some
of the part numbers supercede:
2838931 supercedes to 52068153
2838933 supercedes to 52068155
2838935 supercedes to 52068157
2838936 supercedes to 52068158
2838939 supercedes to 52068061
2838940 supercedes to 52068062
2538942 and 2538943 have not changed
beepbeep
Moparts Member
Posts: 4039
From: Orange, CA. USA
Registered: Dec 2000
posted 05-25-2002 11:08 AM
The numbers shown are original numbers, some are superceded to 52xxxx numbers, the dealer can do that.
1966-1989 727 & 904 Automatics Transmissions
AXLE
RATIO
-------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
Teeth color
24 White, 25 Blue, 26 Red, 27 White, 28 Blue, 29 Black, 30 Yellow, 31 Green
32 Black, 33 Yellow, 34 Green, 35 Orange, 36 Red, 37 White, 38 Blue
39 Green, 40 Orange, 41 Red, 42 White, 43 Blue, 44 Black, 45 Yellow
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
With this tire size and 3.55 Gears, would use 34 Tooth Speedometer gear
Also make sure that the correct number of teeth installed corresponds to the settings on the outside of the retainer.
1957 - 1965 Automatic Transmissions
No longer available from dealers. Junk Yards are the best place to find these.
2204355 16 teeth - 2204356 17 teeth - 2204357 18 teeth
2204358 19 teeth - 2204359 20 teeth - 2204360 21 teeth
Brown 16 Teeth, Orange 17 Teeth, Purple 18 Teeth, White/Tan(HD) 18 Teeth
Blue 19 Teeth, Green 20 Teeth, Black(HD) 20 Teeth, Gray 21 Teeth
TOOTH COLOR PN#
24 WHITE 3410024
25 BLUE 3410025
26 RED 2538926
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
41 RED 2538941
42 WHITE 2538942
43 BLUE 2538943
44 BLACK 2538944
45 Yellow 2538945
Or, better yet go to
http://www.ringpinion.com/Calc_RPM.aspx
after determining your tire size, best found on the tire manufacturers website, or somewhere like tirerack.com, then plug in the diameters and gear ratio on Randy's webpage to see the RPM's.
