The context matters.

A vehicle may use “G” as a terrain-related low gear, but another vehicle could use the same letter for something entirely different.

This is why it would be misleading to say:

“Every manual transmission with a G uses it for off-road driving.”

That is not true.

If you encounter an unfamiliar gear marking in a specific vehicle, consult the transmission diagram or owner’s manual before using it.

A manual transmission should never be operated based solely on something seen in an online article.

The Engineering Behind the Mystery

Perhaps the most interesting lesson here is that a tiny letter on a gear knob can represent a surprisingly sophisticated engineering decision.

Engineers have to balance:

Engine power

Wheel torque

Vehicle speed

Gear ratios

Clutch load

Heat generation

Traction

Fuel consumption

Driver control

A crawler gear is one solution to a very specific problem.

The vehicle needs to move slowly.