Rowells Inc.




Dual Range Auxiliary Transmission Gear Ratio Chart

Use the instructions below to calculate Dual Range gear ratios
or click on your desired application.

 

Ratios Typical Automatic Transmission Typical Manual
Transmission		 Dual Range
Auxiliary Transmission
1st Gear 2.48:1 1st Gear 6.56:1 Underdrive 1.25:1
2nd Gear 1.48:1 2nd Gear 3.58:1 Overdrive 0.80:1
3rd Gear 1.00:1 3rd Gear 1.70.1
4th Gear 1.00:1
How to Calculate

Drive Ratio = Primary Trans. Ratio x Vehicle Differential (Ring & Pinion) Ratio x Dual Range Ratio

Example:
Vehicle equipped with a 4.10 differential AND Dual Range Overdrive Transmission would have the following final drive ratio in Overdrive:

Final Drive Ratio = 1.00 (3rd Gear) x 4.10 (differential) x 0.80 (Dual Range)
                              = 3.28

 

Common Automatic Transmission Ratios
Make Transmission 1st Gear 2nd Gear 3rd Gear O/D
Ford C6 2.46 1.46 1.00 N/A
  E40D 2.71 1.54 1.00 0.71
GM T350 2.52 1.52 1.00 N/A
  T400/475B 2.48 1.48 1.00 N/A
  T700R4 3.06 1.63 1.00 0.70
  T4L80E 2.48 1.48 1.00 0.75

 

Common Manual Transmission Ratios
Make Transmission 1st Gear 2nd Gear 3rd Gear 4th Gear O/D
Ford T18/19 (diesel) 4.02 2.41 1.41 1.00 N/A
  T18/19 (gas) 5.11 3.03 1.79 1.00 N/A
  ZF5 (diesel) 4.14 2.37 1.42 1.00 0.76
  ZF5 (gas) 5.72 2.94 1.26 1.00 0.76
GM SM465 6.56 3.58 1.70 1.00 N/A
  NV4500 6.34 3.44 1.71 1.00 0.73

 

 

T350 3 Speed Automatic Underdrive

    

T350 3 Speed Automatic Overdrive

Axle Ratio 3.08 3.42 3.73 4.10   Axle Ratio 3.08 3.42 3.73 4.10
Under 9.70 10.76 11.75 12.91   First 7.76 8.62 9.40 10.33
First 7.76 8.62 9.40 10.33   Over 6.20 6.89 7.52 8.26
Under 5.85 6.50 7.08 7.78   Second 4.68 5.20 5.67 6.23
Second 4.68 5.20 5.67 6.23   Over 3.74 4.16 4.53 4.98
Under 3.85 4.28 4.66 5.13   Third 3.08 3.42 3.73 4.10
Third 3.08 3.42 3.73 4.10   Over 2.46 2.73 2.98 3.27
                     
 

T400/475 3 Speed Automatic Underdrive

     T400/475 3 Speed Automatic Overdrive
Axle Ratio 3.42 3.73 4.10 4.56   Axle Ratio 3.42 3.73 4.10 4.56
Under 10.60 11.56 12.71 14.14   First 8.48 9.25 10.17 11.31
First 8.48 9.25 10.17 11.31   Over 6.78 7.40 8.13 9.05
Under 6.33 6.90 7.58 8.44   Second 5.06 5.52 6.07 6.75
Second 5.06 5.52 6.07 6.75   Over 4.04 4.42 4.85 5.40
Under 4.28 4.66 5.13 5.70   Third 3.42 3.73 4.10 4.56
Third 3.42 3.73 4.10 4.56   Over 2.73 2.98 3.28 3.65
                     
  T700R4 4 Speed Automatic Underdrive     T4L80E 4 Speed Automatic Underdrive
Axle Ratio 3.42 3.73 4.10 4.56   Axle Ratio 3.42 3.73 4.10 4.56
Under 13.08 14.26 15.68 17.63   Under 11.22 11.56 12.71 14.13
First 10.47 11.41 12.55 13.95   First 8.48 9.25 10.17 11.31
Under 6.96 7.60 8.35 9.28   Under 6.33 6.90 7.58 8.43
Second 5.57 6.08 6.68 7.43   Second 5.06 5.52 6.07 6.75
Under 4.28 4.66 5.13 5.70   Under 4.28 4.66 5.13 5.70
Third 3.42 3.73 4.10 4.56   Third 3.42 3.73 4.10 4.56
Under 2.98 3.26 3.58 3.98   Under 3.21 3.50 3.85 4.28
Fourth 2.39 2.61 2.87 3.19   Fourth 2.57 2.80 3.08 3.42
                     
  SM465 4 Speed Manual Underdrive     SM465 4 Speed Manual Overdrive
Axle Ratio 3.42 3.73 4.10 4.56   Axle Ratio 3.42 3.73 4.10 4.56
Under 28.00 30.54 33.58 37.34   First 22.40 24.43 26.86 29.87
First 22.40 24.43 26.86 29.87   Over 17.92 19.54 21.49 23.90
Under 15.30 16.69 18.35 20.40   Second 12.24 13.35 14.68 16.32
Second 12.24 13.35 14.68 16.32   Over 9.79 10.68 11.74 13.06
Under 7.26 7.93 8.71 9.69   Third 5.81 6.34 6.97 7.75
Third 5.81 6.34 6.97 7.75   Over 4.65 5.07 5.58 6.20
Under 4.28 4.66 5.13 5.70   Fourth 3.42 3.73 4.10 4.56
Fourth 3.42 3.73 4.10 4.56   Over 2.74 2.98 3.28 3.86

 

  C6/C6B 3 Speed Automatic Underdrive
Axle Ratio 3.55 3.73 4.10 4.56 4.88
Under 10.91 11.48 12.61 14.03 15.00
First 8.73 9.48 10.09 11.22 12.00
Under 6.48 6.81 7.49 8.33 8.90
Second 5.18 5.45 5.99 6.66 7.12
Under 4.44 4.66 5.13 5.70 6.10
Third 3.55 3.73 4.10 4.56 4.88
           
  C6/C6B 3 Speed Automatic Overdrive
Axle Ratio 3.55 3.73 4.10 4.56 4.88
First 8.73 9.18 10.09 11.22 12.00
Over 6.98 7.34 8.07 8.98 9.60
Second 5.18 5.45 5.99 6.66 7.12
Over 4.14 4.36 4.79 5.33 5.70
Third 3.55 3.73 4.10 4.56 4.88
Over 2.84 2.98 3.28 3.65 3.90

  E40D/4R100 4 Speed Automatic Underdrive   

E40D/4R100 4 Speed Automatic Overdrive
Axle Ratio 3.55 3.73 4.10 4.63 4.88 5.13   Axle Ratio 3.55 3.73 4.10 4.63 4.88 5.13
Under 12.02 12.64 13.88 15.68 16.54 17.38   First 9.62 10.11 11.11 12.55 13.23 13.90
First 9.62 10.11 11.11 12.55 13.23 13.90   Over 7.69 8.09 8.88 10.04 10.58 11.12
Under 6.83 7.19 7.88 8.91 9.40 9.87   Second 5.47 5.75 6.31 7.13 7.52 7.90
Second 5.47 5.75 6.31 7.13 7.52 7.90   Over 4.38 4.60 5.04 5.70 6.02 6.32
Under 4.43 4.66 5.13 5.78 6.10 6.41   Third 3.55 3.73 4.10 4.63 4.88 5.13
Third 3.55 3.73 4.10 4.63 4.88 5.13   Over 2.84 2.98 3.28 3.70 3.90 4.10
Under 3.15 3.31 3.63 4.11 4.33 4.56   Fourth 2.52 2.65 2.91 3.29 3.46 3.64
Fourth 2.52 2.65 2.91 3.29 3.46 3.64   Over 2.01 2.12 2.32 2.63 2.77 2.91

ZF 5 Speed (Gas) Manual Underdrive   ZF 5 Speed (Diesel) Manual Underdrive
Axle Ratio 3.55 3.73 4.10 5.13   Axle Ratio 3.55 3.73 4.10 5.13
Under 25.38 26.67 29.31 36.67   Under 18.37 19.30 21.21 26.55
First 20.31 21.34 23.45 29.34   First 14.70 15.44 16.97 21.24
Under 13.05 13.71 15.06 18.85   Under 10.51 11.55 12.15 15.20
Second 10.44 10.97 12.05 15.08   Second 8.41 8.84 9.72 12.16
Under 7.15 7.51 8.25 10.32   Under 6.30 6.63 7.28 9.10
Third 5.72 6.01 6.60 8.26   Third 5.04 5.30 5.82 7.28
Under 4.43 4.66 5.13 6.41   Under 4.44 4.66 5.13 6.41
Fourth 3.55 3.73 4.10 5.13   Fourth 3.55 3.73 4.10 5.13
Under 3.38 3.53 3.90 4.88   Under 3.38 3.53 3.90 4.88
Fifth 2.70 2.83 3.12 3.9   Fifth 2.70 2.83 3.12 3.90

  T19 4 Speed Manual Underdrive   T19 4 Speed Manual Overdrive
Axle Ratio 3.55 3.73 4.10   Axle Ratio 3.55 3.73 4.10
Under 22.68 23.83 26.19   First 18.14 19.06 20.95
First 18.14 19.06 20.95   Over 14.51 15.25 16.76
Under 13.45 14.13 15.53   Second 10.76 11.30 12.42
Second 10.76 11.30 12.42   Over 8.61 9.04 9.94
Under 7.94 8.35 9.18   Third 6.35 6.68 7.34
Third 6.35 6.68 7.34   Over 5.08 5.34 5.87
Under 4.44 4.66 5.13   Fourth 3.55 3.73 4.10
Fourth 3.55 3.73 4.10   Over 2.84 2.98 3.28
 
518 4 Speed Automatic Underdrive   518 4 Speed Automatic Overdrive
Axle Ratio 3.55 4.10   Axle Ratio 3.55 4.10
Under 10.88 12.56   First 8.70 10.05
First 8.70 10.05   Over 6.96 8.05
Under 6.43 7.44   Second 5.14 5.95
Second 5.14 5.95   Over 4.11 4.76
Under 4.44 5.13   Third 3.55 4.10
Third 3.55 4.10   Over 2.84 3.28
Under 3.13 3.54   Fouth 2.50 2.83
Fourth 2.50 2.83   Over 2.00 2.26
             
NV4500 5 Speed Manual Underdrive   NV4500 5 Speed Manual Overdrive
Axle Ratio 3.55 4.10   Axle Ratio 3.55 4.10
Under 24.90 28.75   First 19.92 23.00
First 19.92 23.00   Over 15.94 18.40
Under 13.49 15.58   Second 10.79 12.46
Second 10.79 12.46   Over 8.63 9.96
Under 7.41 8.56   Third 5.93 6.85
Third 5.93 6.85   Over 4.74 5.48
Under 4.44 5.13   Fouth 3.55 4.10
Fourth 3.55 4.10   Over 2.84 3.28
Under 3.29 3.79   Fifth 2.63 3.03
Fifth 2.63 3.03   Over 2.10 2.42
             
Under 24.90 28.75   Reverse 19.92 23.00
Reverse 19.92 23.00   Over 15.94 18.40
             
NV5600 6 Speed Manual Underdrive   NV5600 6 Speed Manual Overdrive
Axle Ratio 3.54 4.10   Axle Ratio 3.54 4.10
Under 24.91 28.85   First 19.93 23.08
First 19.93 23.08   Over 15.94 18.46
Under 14.96 17.32   Second 11.97 13.86
Second 11.97 13.86   Over 9.58 11.09
Under 9.03 10.45   Third 7.22 8.36
Third 7.22 8.36   Over 5.78 6.69
Under 6.15 7.13   Fourth 4.92 5.70
Fourth 4.92 5.70   Over 3.94 4.56
Under 4.43 5.13   Fifth 3.54 4.10
Fifth 3.54 4.10   Over 2.83 3.28
Under 3.23 3.74   Sixth 2.58 2.99
Sixth 2.58 2.99   Over 2.06 2.39
             
Under 24.91 28.85   Reverse 19.93 23.08
Reverse 19.93 23.08   Over 15.94 18.46
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