Many motorhomes use heavy-duty, fully-automatic transmissions. Allison Transmission is a leading manufacturer of transmissions for motorhomes and truck RVs. Automatic transmissions in motorhomes reduce stress and enable safe driving, because the driver does not have to take a hand off of the steering wheel to shift gears.
The typical gas-powered motorhome runs with a four-speed automatic transmission. For extra power and reduced engine wear, some owners add an auxiliary two-speed transmission that mounts behind the original transmission. The auxiliary doubles the number of gear ratios to improve fuel efficiency in rough terrain and high winds. Under certain conditions, the additional gears on a Class A motorhome can save several miles per gallon in fuel consumption and keep the vehicle's transmission and engine from overheating.