The VT20-E/VT25-E is a fully-automatic, continuously-variable, front-wheel drive transmission. It consists primarily of a four-element torque converter, one planetary gear set, an electronic hydraulic pressurization and control system, two variable drive pulleys, two friction clutches and, a differential assembly.

The four-element torque converter contains a pump, a turbine, a pressure plate splined to the turbine, and a stator assembly. The torque converter acts as a fluid coupling to smoothly transmit power from the engine to the transmission. It also hydraulically provides additional torque multiplication when required. The pressure plate, when applied, provides a mechanical "direct drive" coupling of the engine to the transmission.

The planetary gear set provides REVERSE. Changing drive ratios is fully automatic and is accomplished through the use of a transmission control module (TCM). The TCM receives and monitors various electronic sensor inputs and uses this information to control the transmission ratios at the most optimum time.

The ratio control motor is used to change drive ratios, and feedback from the speed sensors supplies information to the TCM. The TCM then uses this information to determine when to apply and release the torque converter clutch. This allows the engine to deliver the maximum fuel efficiency without sacrificing vehicle performance.

The hydraulic system primarily consists of a vane type pump, a control valve body, a control solenoid valve assembly, a case and a case cover. The pump maintains the working pressures needed to stroke the clutch pistons that apply or release the friction components. These friction components, when applied or released, support the forward or reverse ranges of the transmission.

The hydraulic system supplies pressurized fluid to the variable drive and driven pulley assemblies to provide accurate variable ratio-controlled output torque to the differential.

The transmission can be operated in any one of the six different positions shown on the shift quadrant.

P: PARK position enables the engine to be started while preventing the vehicle from rolling either forward or backward. For safety reasons, the vehicle parking brake should be used in addition to the transmission "PARK" position. Since the front differential carrier assembly is mechanically locked to the case through the park pawl, variable driven pulley assembly and front differential drive pinion gear assembly, PARK position should not be selected until the vehicle has come to a complete stop.

R:  REVERSE enables the vehicle to be operated in a rearward direction.

N: NEUTRAL position enables the engine to start and operate without driving the vehicle.

D: DRIVE range should be used for all normal driving conditions for maximum efficiency and fuel economy. DRIVE range allows the transmission to operate in the full range of variable ratios. DRIVE allows low to high ratios without any limitations, and torque converter clutch apply. The transmission should not be operated in DRIVE when towing a trailer or driving on hilly terrain. Under such conditions that put an extra load on the engine, the transmission should be driven in a lower range selection for maximum efficiency.

I: Intermediate can be used for conditions where it may be desirable to use only low and intermediate ratios. These conditions include towing a trailer and driving on hilly terrain as described above. The variable ratios are the same as in DRIVE range except that the variable drive pulleys will not be allowed to achieve the higher ratios.

Low: Low can be selected at any vehicle speed. If the transmission is in DRIVE or Intermediate range, it will immediately change the ratio to low when vehicle speed is below approximately 56 km/h (35 mph). This is particularly beneficial for maintaining maximum engine braking when descending steep grades. With Low range selected, the variable drive pulleys will not be allowed to achieve the high or intermediate ratios.