Simplify the following text for a Grade 6 native English-speaking person.
Original: The gearbox provided three forward and reverse gears in either high or low range , with top speed ranging from 5 mph ( 8 km\/h ) in 1st gear , low range up to 36 mph ( 58 km\/h ) .
Simplified: The gearbox provided three forward and reverse gears in either high or low range . It gave a top speed ranging from 5 mph ( 8 km\/h ) in 1st gear , low range up to 36 mph ( 58 km\/h ) .