What similarities do an automatic and a manual transmission have?
Manual and automatic transmissions both accomplish the same thing. They couple the engine to the drive shaft, and they use gears to multiply the engine torque at various vehicle speeds. However, the internal construction of an automatic transmission is quite different from a manual. Most automatics use planetary gears, in an arrangement similar to this: www.procarcare.com/icarumba/resourcecenter/encyclopedia/icar_resourcecenter_encyclopedia_autotrans2.asp Henry Ford used planetary gears on the Model T, but they were manually operated. Automatic transmissions operate using a complex arrangement of electronics, hydraulics, and vacuum components to shift the gears based on engine load and speed. For this reason, they are considerably more complex than manual gearboxes; they are also heavier, more expensive, and less efficient in terms
