Crawl Ratio Calculator

Calculate you Vehicle's Crawl Ratio

Crawl ratio is a term used in the 4 wheel drive and off-road realm as a means of comparing the capability of a vehicle through its ability to crawl. The maximum crawl ratio is calculated using the vehicle's lowest possible gearing, which is provided with the transmission in 1st gear and the transfer case(s) in the lowest range. The higher the crawl ratio, the better the crawling capability of the vehicle. At the same time, as crawl ratio increases (number becomes larger), engine torque transmitted to the wheels increases and crawl speed decreases proportionally. You could say that, in a nutshell, the crawl ratio simply designates a numerical representation of how "low" a vehicle is geared.

Common transmission and transfer case charts can be found below

1st Gear Trans Ratio:

: 1

Transfer Case Ratio:

: 1

Axle Ratio:

: 1

Crawl Ratio:

Transmission Ratio Chart

Transmission Model

1st

2nd

3rd

4th

5th

6th

R

SM465

6.55 : 1

3.58 : 1

1.57 : 1

1.00 : 1

---

---

6.09 : 1

SM420

7.05 : 1

3.57 : 1

1.70 : 1

1.00 : 1

---

---

6.78 : 1

NP435*

6.68 : 1

3.34 : 1

1.66 : 1

1.00 : 1

---

---

8.26 : 1

T-18

6.32 : 1

3.09 : 1

1.69 : 1

1.00 : 1

---

---

7.44 : 1

NV4500*

5.61 : 1

3.04 : 1

1.67 : 1

1.00 : 1

0.75 : 1

---

5.61 : 1

NV5600

5.63 : 1

3.38 : 1

2.04 : 1

1.39 : 1

1.00 : 1

0.73 : 1

5.63 : 1

ZF S5-42/S5-47

5.72 : 1

2.94 : 1

1.61 : 1

1.00 : 1

0.76 : 1

---

5.24 : 1

ZF S6-650

5.79 : 1

3.30 : 1

2.10 : 1

1.31 : 1

1.00 : 1

0.72 : 1

5.23 : 1

GM TH350

2.52 : 1

1.52 : 1

1.00 : 1

---

---

---

1.93 : 1

GM TH400

2.48 : 1

1.48 : 1

1.00 : 1

---

---

---

2.07 : 1

GM TH700R4

3.059 : 1

1.625 : 1

1.00 : 1

0.696 : 1

---

---

2.294 : 1

GM 4L80E/4L85E

2.48 : 1

1.48 : 1

1.00 : 1

0.75 : 1

---

---

2.07 : 1

Chrysler TorqueFlite 727

2.45 : 1

1.45 : 1

1.00 : 1

---

---

---

2.22 : 1

Ford C4/C6

2.46 : 1

1.46 : 1

1.00 : 1

---

---

---

2.18 : 1

Ford AOD/AODE

2.40 : 1

1.47 : 1

1.00 : 1

0.67 : 1

---

---

2.00 : 1

Ford E4OD

2.71 : 1

1.54 : 1

1.00 : 1

0.71 : 1

---

---

2.16 : 1

Ford 4R70W

2.84 : 1

1.55 : 1

1.00 : 1

0.70 : 1

---

---

2.23 : 1

Ford 4R100

2.71 : 1

1.54 : 1

1.00 : 1

0.71 : 1

---

---

2.88 : 1

 

Transfer Case Ratio Chart

Transfer Case

Hi Range

Low Range

Chain/Gear Drive

NP205

1.00 : 1

1.96 : 1

Gear

NP203

1.00 : 1

2.00 : 1

Chain

NP208

1.00 : 1

2.61 : 1

Chain

NP241

1.00 : 1

2.72 : 1

Chain

Dana 18 (41-45, Military)

1.00 : 1

1.97 : 1

Gear

Dana 18 (45-46)

1.00 : 1

2.43 : 1

Gear

Dana 18 (46-71)

1.00 : 1

2.46 : 1

Gear

Dana 20

1.00 : 1

2.00 : 1

Gear

Dana 300

1.00 : 1

2.62 : 1

Gear

BW1345

1.00 : 1

2.72 : 1

Chain

BW1356

1.00 : 1

2.69 : 1

Chain

BW4406

1.00 : 1

2.64 : 1

Chain

BW4407

1.00 : 1

2.69 : 1

Chain