Most of the heavy vehicles are fitted with diesel engines, which generate more vibrations and noise than petrol engines.
When the engine is placed in the front it gives rise vibrations from the engine and the transmission line. It also causes discomfort to the passengers especially in case of long journeys.
If the engine is fitted at the rear it is comfortable to the passengers but problems such as remote operation of accelerator, gear shifting and inferior engine cooling arises.
Rear engines reduce fatigue of the driver. He is also free from noise and vibration from the engine. Moreover, the weight on the front portion of the vehicle is reduced and so the torque needed to steer the vehicle would be less. Also, the hot air from the engine does not enter inside the cabin. However, the cost of manufacturing a rear engine vehicle is higher compared to front engine vehicle.
Fitting engines at the rear side has many advantages. First, the weight of the driving wheels (rear) is increased in slopes. This gives better traction through improved road adhesion.
As the propeller shaft is absent, chassis height can be decreased. Further, the front portion of the vehicle is amenable to better designing and front axle construction can be simplified. But this type has certain disadvantages. They are difficult to service, have decreased cooling efficiency and are unstable at high speeds.
In India, only front engine with front axle drive or rear axle drive is preferred as they give considerable ground clearance which is suitable for the road conditions.