Friction discs
Friction discs are the main components of the third gear clutches of an automatic transmission and consist of the following parts:
* Friction Material: A resin or cellulose based material that provides friction to transmit power.
*Steel Base: A thin steel plate that supports the friction material.
* Splines: Cutouts in the inside of the steel base that allow the disc to slide over the hub.
Types of friction discs
There are two main types of friction discs used in third gear clutches of automatic transmissions:
* Direct Drive Friction Disc: Transfers power directly to the third gear drum.
* Clutch Shaft Friction Disc: Isolates the third gear drum from the transmission, allowing the vehicle to shift into third gear without slipping.
Friction drums
Friction drums are the other main component of the third gear clutch of an automatic transmission and are cylindrical surfaces on which the friction discs press. Drums are usually made of steel and have grooves to dissipate heat and lubricant.
Pistons and piston rings
Pistons and piston rings are used to control the third gear clutches of an automatic transmission. The pistons move under hydraulic fluid pressure and press the friction discs against the friction drums. Piston rings provide a seal between the piston and cylinder and prevent hydraulic fluid from leaking.
Hydraulic piston
The hydraulic piston is a cylindrical piston that moves inside the valve body and controls the hydraulic pressure applied to the third clutch pistons. The position of the piston is controlled by an input signal from the electronic control unit (ECU).