Crawl Ratio Calculator
Enter your transmission, transfer case, and axle gear ratios into the left side of the form below and press the calculate button to find your final crawl ratio.
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Crawl Ratio Calculation Basics
The crawl ratio is the number of rotations your engine makes before your tires make one full turn. The ratio is calculated by multiplying your transmission, transfer case, and ring and pinion gear ratios. Off-road drivers and rock crawlers build their vehicles with low (numerically high) crawl ratios because not only does that increase torque at the wheels, it allows for better throttle response for low speed, technical driving.
[ Transmission Ratio x Transfer Case Ratio x Axle Ratio ] = [ 2.48 x 2.72 x 3.73 ] = [ 25.16 : 1 ]
Popular Transmission and Transfer Case Ratios
| Transmission | 1st Gear | 2nd Gear | 3rd Gear | 4th Gear |
|
| Chrysler TF-727 | 2.45:1 | 1.45:1 | 1.00:1 | |
| Chrysler TF-904 | 2.45:1 | 1.45:1 | 1.00:1 | |
| Chrysler A-500 / 42RH | 2.74:1 | 1.54:1 | 1.00:1 | 0.69:1 |
| Chrysler A-518 / 618 / 47RH | 2.45:1 | 1.45:1 | 1.00:1 | 0.69:1 |
|
| Ford C4 | 2.46:1 | 1.46:1 | 1.00:1 | |
| Ford C6 | 2.46:1 | 1.46:1 | 1.00:1 | |
| Ford AOD | 2.40:1 | 1.47:1 | 1.00:1 | 0.67:1 |
| Ford AODE-W / 4R70W | 2.84:1 | 1.55:1 | 1.00:1 | 0.70:1 |
|
| GM Powerglide (Small Block) | 1.76:1 | 1.00:1 | | |
| GM Powerglide (Big Block) | 1.82:1 | 1.00:1 | | |
| GM 200-4R | 2.78:1 | 1.57:1 | 1.00:1 | 0.67:1 |
| GM TH350 / Turbo 350 | 2.52:1 | 1.52:1 | 1.00:1 | |
| GM TH400 / Turbo 400 | 2.48:1 | 1.48:1 | 1.00:1 | |
| GM 700R4 / 4L60E | 3.06:1 | 1.63:1 | 1.00:1 | 0.70:1 |
| GM 4L80E / 4L85E | 2.48:1 | 1.48:1 | 1.00:1 | 0.75:1 |
|
|
| Transfer Case | High Range | Low Range |
|
| Borg Warner 1339 | 1.00:1 | 2.57:1 |
| Borg Warner 1350 | 1.00:1 | 2.48:1 |
| Borg Warner 1356 | 1.00:1 | 2.72:1 |
|
| Dana / Spicer 18 | 1.00:1 | 1.97 / 2.46:1 |
| Dana 20 | 1.00:1 | 2.34 / 2.46:1 |
| Dana 300 | 1.00:1 | 2.62:1 |
|
| NP 203 | 1.00:1 | 1.96:1 |
| NP 205 | 1.00:1 | 1.96:1 |
| NP 208 / 209 | 1.00:1 | 2.69:1 |
| NP 228 / 229 | 1.00:1 | 2.69:1 |
| NP 231 / NP231HD | 1.00:1 | 2.72:1 |
| NP 241 / NP241HD | 1.00:1 | 2.72:1 |
| NP 261 / 263 | 1.00:1 | 2.76:1 |
| NP 271 / 273 | 1.00:1 | 2.72:1 |
|
To find your axle gear ratio, please see our Ring and Pinion Gear Ratio Calculator |