In order to understand the basic operation of the automatic transmission systems as well as the key components contained in them, it is pivotal top know about some major terms associated with it. The Torque Converter is a mechanical as well as fluid coupling, which connects the engine and the transmission, while acting like the clutch pedal of the standard shift vehicles. The ramping up of the speed ramps leads to spinning of the converter, which further results in the multiplication of the torque owing to the turbine unit design. More often than not, a one -way or sprag clutch is itself used in as a torque converter. Over-spinning of the converter results in increased output as well as efficiency. The decrease in engine speeds results in slowing down of the converter spinning, which must consequently catch up or completely stop, so that the engine might be driven again. Some of the major transmission system problems are enlisted below:
- If the sprag clutch in the automatic transmission system, which is used with the converter, becomes defective, it would not allow the car to go into the low or the reverse mode. If the automatic transmission fluid is fully clean, the problem can be diagnosed by removing the converter and the transmission. The tab inside should be turned with the help of a screwdriver, while the spline is wedged using another screwdriver. If it does not spin freely in one direction, while holding up firmly in the other direction, the converter is in a faulty condition.
- If the transmission system problems cause the automobile to not move at all, the pump pressure might be the plausible underlying cause. Although this problem is rare, as most of the pumps are reliable in nature, a quick check might be conducted by loosening the transmission cooling lines while subsequently starting the engine. A normal pump would spray the fluid under fairly high amount of pressure. However, if the gusher of the fluid is not seen, the pump may be diagnosed as the root cause of the transmission system problems. The transmission filter might also be checked after removing the service pan as a plugged filter can also cause the problems of low pressure.
- Another one of the common transmission system problems is the delayed shifting or the harsh shifting. It might occur sue to the sticking valves inside the valve body or the shift solenoids. The newer breed of automatic transmission has been designed to be computer controlled as they utilize electro magnets for engaging or disengaging shift valves. However, the older transmissions might make use of a valve body. In some of the really old transmission systems, modulator valves might also be used instead of the throttle valves, which rely on the engine vacuum in order to determine the load values. The load values are themselves balanced against the speed or the governor values, for determining the shift points. The computer-based electromagnetic valves have the ability of engaging and disengaging based upon the computed engine values, which in turn simply determine the precise value of the shift points.
- Mechanical failure might also occur sometimes at the gear strips. The same can be diagnosed by looking for the metal shavings, the metal chips or the bronze-colored bushing material. If any of the aforementioned parts are found, the car might have to be overhauled for repair.