Now, (with caution – safety first!), shift the transmission lever into neutral. Apply the parking brake. With the engine idling, press the clutch pedal all the way, hold it down, and listen for noises. Then release the pedal and listen for noises again. There should be no loud noises at either positions. The next step [...]
Posted in Transmission Test
There are several problems that can be resolved with an adjustment (A simple adjustment is one that can be made without removing the transmission from the vehicle.) or minor repair. If a late model transmission (computer-controlled transmissions started becoming popular in the early ’90s) is not shifting properly, it is often the result of a computer [...]
An automatic transmission has many seals and gaskets to control the flow of hydraulic fluid and to keep it from leaking out. There are two main external seals: the front seal and the rear seal. The front seal seals the point where the torque converter mounts to the transmission case. This seal allows fluid to [...]
Computer Controls The computer uses sensors on the engine and transmission to detect such things as throttle position, vehicle speed, engine speed, engine load, brake pedal position, etc. to control exact shift points as well as how soft or firm the shift should be. Once the computer receives this information, it then sends signals to [...]
The Hydraulic system is a complex maze of passages and tubes that sends transmission fluid under pressure to all parts of the transmission and torque converter. The diagram at left is a simple one from a 3-speed automatic from the ’60s. The newer systems are much more complex and are combined with computerized electrical components. [...]
On automatic transmissions, the torque converter takes the place of the clutch found on standard shift vehicles. It is there to allow the engine to continue running when the vehicle comes to a stop. The principle behind a torque converter is like taking a fan that is plugged into the wall and blowing air into [...]
Automatic transmissions contain many gears in various combinations. In a manual transmission, gears slide along shafts as you move the shift lever from one position to another, engaging various sized gears as required in order to provide the correct gear ratio. In an automatic transmission, however, the gears are never physically moved and are always [...]