AW55-50 SN, pliki, AISIN AW55-50SN

Focus Technology Ltd 2003

Asian Warner 55-50SN Seminar

General Description

This transmission is manufactured by Asian Warner. It can be found in many different vehicles such as General Motors, Volvo, Saab, Renault and Fiat.

Although it looks the same, there are subtle differences. We will look at some of them later but it is important to note that not all parts are interchangeable.

The 55-50SN is also referred to as the AF23/33-5 transmission by some manufacturers such as GM.

This transmission incorporates the final drive unit and therefore it is known as a Transaxle. It is a fully operational automatic transmission which has five forward gears and is electronically

Controlled.

There is a four element torque converter in this transmission. In incorporates a, Pump. b, Turbine. c, pressure plate which is located by the spline on the shaft of the turbine, and d, the stator assembly.

The TCM (Transmission Control Module) commands the solenoids to obtain the required ratio. It also controls the line pressure and the apply and release pressure for the torque converter clutch. The input signals from the sensors act to feed information to the TCM so that it can obtain the best ratio to give maximum fuel efficiency.

General Description continued

The hydraulic system follows the normal transmission requirements utilizing a pump along with the valve body case cover and converter housing. The pump produces a variable pressure dependent on engine speed. This is then regulated to produce the working pressure. This pressure works to apply the servo and pistons that apply and release the friction components.

Model Differences

As we have seen, this transmission is fitted to vehicles of many different manufacturers. Although there are similarities with this transmission, it should be noted that there are distinct operational differences. He control strategy for solenoid operation varies from manufacturer to manufacturer. Even when a valve body looks the same, it differs considerable so be careful when changing parts that you do not introduce a fault that you will never fix.

A close study of the component and solenoid application will show that there is distinct differences.

Park, Neutral position switch

The park neutral switch is of a sliding contact type that is connected directly to the manual shift lever. It is fitted externally on the transmission and it is adjustable There are four positions in the switch that inform the TCM which position the gear lever is in. The information is used for control of the engines as well as the transmission. If you are using a scanner, you will see the positions displayed as Modes, A, B C and PA. The switches on each vehicle look the same but are not. Make sure that you have the correct on fitted.

Neutral control

Volvo vehicles using the 5 cylinder engine since 2001 have a neutral control circuit fitted to reduce emissions and fuel consumption. The TCM will operate the appropriate solenoids to place the transmission in neutral when the car is standing with the brakes applied in the “D” position. Transmission fluid temperature must be in the normal operating range for this feature to be active. The gas pedal must not be depressed as the accelerator pedal module (APM) will tell the PCM that the vehicle should be moving.

Re-engagement of first gear is done as the brake pedal sensor indicates that the brake is no longer depressed.

AW 55-50 SN with Modulated lock-up

This transmission is an electronically controlled five speed automatic transmission. In Volvo it is fitted to the X70 series. It is derived from the AW 50-42 transmission with the following differences.

· A fourth planetary gear. (P4)

· Free wheel F3 has been eliminated

· The TCC has a slip strategy

· A fifth brake (B5) has been added

· Four more solenoids

· Four small differential pinions in the final drive

· Accumulators have been removed

Gear changes

The gear changes and lock up functions are controlled by the activation of the solenoids as described in the patterns later. Be sure to remember that the valve bodies are not interchangeable between models as the shift patterns differ.

There are two change patterns available: Normal and Winter modes

In normal mode, shifts and lock-up take place relatively early to improve fuel consumption. If the throttle is moved rapidly, the TCM will engage a SPORT mode.

In the winter mode, the changes will be at lower engine speeds. 1st and 2nd gear will also be available for kick down.

Selector position D,4,3….. The car will start off in 3rd gear

Selector position L………..The car will start off in 2nd gear.

Engine braking will be available in “L” by application of the B3 brake