What is the Ford Bronco’s Crawler Gear and How it Works

The function is nothing revolutionary and has graced off-roading trucks and SUVs for more than 25 years.

The Granny Gear, as it is affectionately called, was featured on the Chevrolet Blazer’s SM465 transmission back in 1991. It allows the driver to shift to a lower gear that is similar to first but allows much lower speeds while maximizing wheel torque to help the vehicle navigate extreme terrain.

On the Bronco’s manual transmission an extra ‘C’ gear is present and noticeable on the shift knob. It can be engaged by pulling the shifter all the way to the bottom right, in the opposite direction of the reverse gear.

To understand crawl ratios, we can analyze the Bronco’s first gear, which has a ratio of 4.2:1. What this means is that for every 4.2 engine rotations, the wheels rotate once.

The crawler gear has a ratio of 6.588:1 and when it is paired with the shorter 3.06:1 low gear of the transfer case and the shortest final drive gear of 4.70:1, the overall crawl ratio is 94.7:1 which delivers an extreme amount of torque while rotating the wheels at very low speeds. This is called torque multiplication.

In theory, the smaller 2.3-liter inline-four would send 29,372 lb.-ft of torque to the wheels, which is an astonishing amount of power that cannot be fully used.

This is where most car manufacturers, especially when marketing EVs, tend to promote these figures over engine torque to amaze the public. In reality, this much power cannot be utilized in a real-world scenario since it would send way too much power to the wheels and over-spin them when you need grip the most.

The super-low gear is not all about delivering huge amounts of torque but rather allows more accurate throttle control instead of overpowering the tires and thus losing grip when you need it the most.

It also allows you to ease off the clutch at slow speed, which is extremely useful when you must clear difficult obstacles, and gives you the freedom of just concentrating on the task at hand rather than worrying about burning or slipping the clutch.

The crawl gear is also available on the ten-speed automatic transmission but has a 67.8:1 crawl ratio. This might sound less powerful than what the manual transmission has to offer but keep in mind that the automatic is aided by a torque converter so you should not have any difficulties clearing obstacles with the same ease that you would with a manual gearbox.

The new Bronco is set to roam the trails starting next year and it will be interesting to experiment with the crawler gear firsthand. The capable Badlands model will start at $42,000 for the two-door version and the fully-loaded First Edition will set you back at least $57,000.