Diesel engines produce tremendous torque and power, essential elements in driving a heavy vehicle like a motor home. Mated to a heavy-duty automatic transmission, they are the perfect solution to pushing a heavy vehicle around the country.
A diesel is said to be a pusher when the engine is mounted in the rear of the vehicle, thus giving the appearance of pushing the bus. They still operate like a front-engine, rear-drive vehicle--only backward. They are not connected directly to the axle like a front-wheel drive car.
Noise reduction followed by interior design flexibility are the most important elements in a motor home or bus layout. Placing the engine in the rear eliminates the characteristic hump in the front, reduces vibration from the drive-shaft, opens the floor space and undercarriage for more storage and eliminates the noise of the engine from the passenger compartment.
Pushers are much more expensive than front-engine coaches, partly because the diesel engine is more costly and much heavier than its gasoline counterpart. The result is that the chassis must be heavier and is more expensive to manufacture. Because of the tremendous flexibility in design, pushers tend to be more exotic and luxurious than your average motor home and are priced accordingly.
In addition to the noise and space elements, pushers are inherently safer and easier to drive. The heavy engine is not going to come crashing down the aisle if you hit something. The wheelbase is not limited by the length of the drive-shaft, so it can be extended to give a better ride and reduce the tail slap caused by a long overhang in the rear.
