The automatic transmission system is one that can shift gear ratios as the vehicle is moving without having to do the job manually. While the manual transmission system requires one to press the clutch, detach the engine contact and then shift the gear, the automatic transmission requires none. The main difference between a manual and an automatic transmission is that while the manual transmission shifts between different sets of gears to the output shaft to achieve the various gear ratios, in an automatic transmission, different gear ratios are produced by the same set of gears.
Components
The internal arrangement of the automatic transmission system is fairly complex with a lot of components. These are arranged within a small space and among a lot of other things, one can see:
- A planetary gear set.
- A set of bands to lock parts of a gear set.
- A set of three wet-plate clutches to lock other parts of the gear set.
- An odd hydraulic system that controls the clutches and bands.
- A large gear pump to move transmission fluid around.
A crucial aspect of an automatic transmission system is the planetary gear set. All the other parts of the gearbox are there only to help it perform it work properly. The components of the planetary gear set are:
- The sun gear
- The planet gears and the planet gears’ carrier
- The ring gear
- Carrier
Unlike in manual transmission gears, in automatic transmission system the gears may be input, output or stationary. It always depends on the role that each of these gears plays.
Advantages of an automatic transmission system:
- Increased driver comfort.
- Easy to use, when compared to Manual transmissions.
- Good at hill climbing.
- The engine stays on ignition and will not die.
- The number of speeds are far more than in manual transmission.
Disadvantages of an automatic transmission system:
- It increases the weight of the vehicle.
- Maintaining a vehicle with automatic transmission is expensive given the fact the oil and filters will have to be replaced regularly.
- Better in stop-and-go traffic.
- It overheats easily.
Back in the days when automatic transmission system was introduced, they were unreliable and slow. But those disadvantages have been rectified and the disadvantages that are there are minimal. Owing to some of the advantages that manual transmission systems have over automatic ones, some vehicles today come equipped with both manual and automatic systems. They can be switched between themselves whenever needed.