Automatic transmission: torque converter, dsg and cvt – the advantages and disadvantages of the transmission types

Shift lever of an automatic transmission

Automatic transmissions make for relaxed driving and are becoming increasingly popular. What are the differences between the different versions of the?

  • There are three main types of automatic transmission: torque converter automatic, continuously variable automatic transmissions (CVT) and dual-clutch transmissions (DKG/DSG)
  • The torque converter automatic is the most widespread, a CVT transmission gets along without shift pauses
  • Expensive and technically complex are the double-clutch transmissions

A automatic transmission shifts gears independently for the driver. So the automatic stands for relaxed driving. However, the manual transmission masters both the history as well as (still) the present, because in europe over 65 percent of vehicles drive with manual transmissions. Automated manual transmissions, in which actuators take over the operation of the mechanical clutch and the transmission, are a cost-effective speciality. Due to long gearshift pauses with interruption of traction, this type of transmission has not become established in all vehicle segments. Only frequently used in inexpensive small cars.

Overview of automatic transmissions

the prime choice for fast gear changes is the dual-clutch transmission. The structure one „DKG" special version looks like the next gear is already in stand-by mode while the watch is still running. This virtually cancels out the traction interruption. Besides the DKG, the most comfortable automatic, there are also continuously variable transmissions (CVT). Driving is even more comfortable with a torque converter transmission. The speed at the transducer is very low.

Converter gears: the advantages and disadvantages

converter gearbox describe the classic automatic transmission, which in comparison to CVT and DKG or. DSG with 2.000 euro is on a par in terms of price. The heart of this principle is the torque converter. It consists of a guide wheel, turbine wheel and pump wheel and is permanently installed in a housing. At idle speed the converter only a minimum to move the vehicle with the brakes off. Acceleration sets the transmission oil in motion and captures the turbine wheel. Due to the back pressure of the oils torque is increased at the blades. Especially in the USA the converter is strongly represented. No wonder, since general motors in detroit was the first to install a torque converter transmission as standard in a vehicle.

Advantages of the torque converter automatic:

  • Low load on components, little wear and tear
  • Good efficiency
  • Minimal traction interruption
  • The converter dampens vibrations in the drivetrain

The disadvantages of the torque converter automatic:

  • Power transmission not optimal
  • Towing with a rolling drive axle is not possible with some models
  • Relatively expensive

CVT: advantages and disadvantages of the continuously variable automatic transmission

The continuously variable automatic transmission – short: CVT – owes its abbreviation to the english term "continuoulsy variable transmission". So it stands for a continuously variable transmission. Compared to the converter in a converter transmission and to DKG or. DSG is the continuously variable automatic comparatively cheap. About 1.000 euros costs the purchase.

Advantages of the CVT:

  • Jerk-free driving without traction interruption
  • CVT transmissions are small, light and inexpensive
  • modern CVT transmissions are economical because the engine usually stays in the most efficient speed ranges

Disadvantages of the CVT:

  • Loud when accelerating
  • stress on components, comparatively maintenance-intensive
  • The only possible disadvantage is the so-called "rubber band effect", i.e. acceleration at a constant speed. The acoustics take some getting used to.

DKG: advantages and disadvantages of the double clutch transmission

The dual clutch transmission – short: DKG – offers the comfort of a automatic transmission with the efficiency of a manual transmission type. The dual clutch transmission consists of two gearboxes and two clutches. DKG is not a standard designation used by all manufacturers. Instead call VW, skoda, seat and bugatti the technology direct shift transmission (DSG). at ferrari, fiat, hyundai and mercedes-benz the technology is called DCT (double clutch transmission). DKG, DSG and DCT thus differ from converter transmissions with converter and of continuously variable automatic transmissions (CVT).

Advantages of a dual clutch transmission:

  • Fast gear changes
  • High efficiency
  • Cheaper than torque converter automatic transmissions
  • compact design
  • No "creep", maneuvering needs more feeling in the driver’s throttle foot
  • High weight
  • Wear and tear during starting/shunting

The automatic transmission in the workshop

If the repair of a automatic transmission because the vehicle has its function no longer or not fully complies, it is advisable to visit a specialist company- no matter which transmission it is (converter gearbox with converter, DKG/DSG, CVT). Installing a new automatic transmission is a major step in terms of costs about 10.000 euro mostly not profitable. Instead, an alternative may be to purchase a replacement transmission at an acquisition cost of 2.000 euro and the cost of removal and installation to order.

If the gearshift is not smooth, the start is delayed or the vehicle vibrates, this may indicate a defect in the automatic transmission. The specialist in a workshop will check the control units for faults and the oil level during a test drive and in the workshop. In order to prevent damage, experts recommend that the transmission be flush and directly in the course of the flush of the gearbox to change the gearbox oil.

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