8.1. General information
On the cars considered in the present manual the automatic transmission (AT) of U140E (the front-wheel models delivered on the American market) or U140F (all-wheel drive models) is established. Below AT U140F is considered.
AT U140F design
The components involved in work of AT
At the time of start-off from the place of AT acts as ordinary coupling, and during the movement performs work on gear shifting.
The AT main hubs are: torque converter (hydrotransformer), planetary reducer and hydraulic or electronic control unit. Hydrodriving disk brakes and disk coupling are applied to transition to other transfer relation in a planetary reducer.
The torque converter on the functions corresponds to hydraulic coupling. Its task includes implementation of coupling at start-off from the place and gear shifting.
The control system of transmission is a component of a control system of the engine and on the basis of the analysis of the data arriving from various information sensors (not necessarily directly related to functioning actually of transmission), chooses optimum from the point of view of profitability, smoothness of switchings and so forth the mode of functioning of AT. At failure detection in memory of the control unit the corresponding code registers (see Specifications to the Head Sistemy of electric equipment of the engine).
Components of a control system of transmission
The only procedure of service of AT which implementation has to be made on a regular basis is check of level of its working liquid (ATF) which order of performance is stated in the Head Nastroyki and routine maintenance of the car. Need for regular replacement of ATF is absent.
Near a radiator of the cooling system of the engine ATF cooler is established.
Operating modes of transmission are described in the Head Governing bodies and methods of operation.
Thanks to application of D/V of the P / N modes start of the engine can be carried out only when the lever of the AT selector is in situation "P" or "N" that allows to prevent the casual movement of the car in start attempt.
In the present chapter only the most general procedures of service of AT lying within qualification of the average amateur mechanic are considered.