There are primarily two types of transmission styles, automatic and manual (stick shift). The automatic transmission utilizes a series of planetary gear sets to obtain the different gear selections, a hydraulic clutch engagement system controlled by the PCM (power control module). A series of fluid control solenoids and a torque converter which is a fluid coupler that allows the engine to run while the car is stopped without stalling the engine, and re-engage to make the car move. There is a cooler located in the radiator to cool the transmission fluid before it is returned to the transmission. The transmission connects to the rear of the engine in most cases.

The power from the engine is transferred into the transmission through an input shaft and the output power to the drive line (wheels) through the output shaft. Most automatic transmissions have a service filter in the transmission pan that needs to be changed regularly. When servicing an automatic transmission a complete fluid flush is recommended, there are many passages inside the transmission and a complete flush is the only way to assure a proper transmission fluid service.

A manual transmission consists of a series of heliacal gears, syncros, roller bearings, counter shafts, gear selector forks and a main clutch assembly that engages and disengages the engine from the manual transmission. The heliacal cut gears are used to select the gear desired, the sector fork move the gears from one gear to the next when the gear shift knob is manually activated. The syncros are used to slow the gear to a stop before it is engaged to avoid gear grinding, the counter shafts hold the gears in place against the main input shaft. And the main clutch assembly allows the engine to be disengaged from the transmission and re-engage when desired. A stick shift transmission has no torque converter so there is no need for a transmission cooler. A stick shift transmission needs a simple fluid change for proper service. (there is no transmission filter for a stick shift transmission).

Transmission Noises and Problems:

Transmission malfunctions can be a minor or a major problem, we will inform you of some quick checks to help determine what kind of problem you have.

Automatic Transmission

Automatic transmissions make specific noises when a malfunction is occurring. An automatic transmission is a hydraulic pressure driven system that can make different noises than a manual transmission. If the transmission filter becomes plugged do to debris in the transmission, it can make a whining noise that follows the engine RPM. If the fluid level is low it can cause a gurgling sound, this sound is do to fluid scavenging inside the transmission. Most automatic internal failures are do to bearing, clutch or hard part failure. When such a failure has occurred the transmission can make grinding, worrring or no noise at all. When a transmission has a major failure you might hear a loud pop, this could be a drive component inside the transmission has failed causing the vehicle to stop moving.

Check this link: Automatic Transmission