Checks and adjustments of a mehaniko-hydraulic part

Stall-Test

The general information

Stall-Test It is applied to check of serviceability of functioning of the converter of rotation (hydrotransformer) and an estimation of keeping ability of brake assemblages and friction clutches трансмиссионной assemblages.

One of defining conditions of performance of check is serviceability of a condition and correctness of adjustment of the power unit, - check up levels of a cooling liquid, impellent oil and ATF

Check is made at working, heated-up to normal working temperature, the engine and put on transfer АТ, - do not forget to cock a lay brake and to prop up wheels противооткатными boots.

For carrying out of check Stall-Test the good tachometre and спецификационная a card of turns of the engine is required. Tachometre connection should be made strictly according to instructions of manufacturers of the device, - try to place a measuring instrument so that its dial was well looked through from a driver's place.

The main lack of described check is potential possibility of an overheat of transmission. For the given reason not all manufacturers publish спецификационные cards of turns Stall-Test. Nevertheless, Stall-Test uses wide popularity among the experts who are engaged in regenerative repair of automatic transmissions for whom manufacturers АТ can let out the special bulletins made on the basis of carrying out of intrabranch research works.

Order of performance of procedure

Check of a delay of the response (Time-Lag-Test)

Check of the main pressure

Trial runs

If АТ it is suspected of infringement of serviceability of functioning, first of all always it is necessary to try to be defined with representation of character of refusal.

On firm car repair shops it is usually possible to order a card of switchings АТ where the moments of switching of transmission provided by specifications are specified at various operational parametres (speed, loading, vehicle type, a switching direction). In the most detailed cards such additional parametres, as standard installations on operating pressure of a drive of friction clutches and brake assemblages can be specified. Besides, explanatories on interpretation of infringements revealed during trial runs here can be resulted. Comparison of parametres of the actual switchings which were taking place at trial runs, with a corresponding card will help to localise possible sources of malfunctions.

There are two ways of carrying out of trial runs. In the first case at the wheel a vehicle there should be personally an owner of the car that will allow checking to make sure of adequacy of skills of its driving to requirements of a card of switchings. In the second case test arrival is made in free from traffic a safe place, - the skilled mechanic-driver with the assistant make detailed verification of parametres of functioning of transmission with a card of switchings. During test work of units of transmission, the engine and systems of their management is checked. Normal work АТ depends, in many respects, on serviceability of functioning of the engine in this connection, to this unit during tests it is given not less attention, than most АТ.

At definition of the moments of switching of transmission correctness of parities of operating pressure of a throttle and a centrifugal regulator is actually checked at various loadings on the engine. One more factor to which special attention should be given during tests, absence of stress of switchings of transmission is. Switchings can occur in exact conformity to card requirements, however infringement of their smoothness, or excessive инерционность will be powerful arguments in favour of necessity of performance of check of a condition of hydroaccumulators.

During test arrival all possible high-speed and loading modes should be checked up, - completeness of the collected information is pledge of correctness of conclusions. It is necessary to give special attention to behaviour of a vehicle under the conditions described by the owner when infringements took place, - accuracy of definition of conditions of refusal is the basic factor at revealing of its source.

In case of revealing of the insignificant malfunctions expressed in infringement of external adjustments or failure of elements which replacement does not demand dismantle of transmission from the car, corresponding procedures are made on a place. If malfunction has serious character performance of major repairs of transmission is offered to the client.

During tests transmission should be heated-up to normal working temperature (70 80 ).

Make sure of serviceability of activation of switching kickdown in a mode D, - switchings should take place in all provided combinations: O/D 3, O/D 2, O/D 1, 3 2, 3 1 and 2 1.

In case of revealing of unusual noise or vibrations try to define the nature of their occurrence. The most probable sources noise and vibrating фонов are the hydrotransformer, power shafts/kardannye and differentials. It is necessary to trace dependence of occurrence of noise/vibrations on initial parametres at car movement in a mode D: O/D with hydrotransformer blocking, O/D without hydrotransformer blocking, 3rd transfer (at included special mode HOLD).

Compare results of supervision to the card of infringements resulted more low.

The analysis of results of trial runs, operations procedure on elimination of malfunctions