Saab:: 9-5: General information

9.1. General information

Location of identification number AT and its interpretation are described in the Section Identification of Transmission.

On the cars considered in the present manual till 2002 AF30 AT, and since 2002 – AT AF33-5 were established.

Components of management of AT


245 — the Sensor of position of the selector of the AT modes 502 — TCM 506 — the Switch of the Winter mode 532 — the Sensor of speed of a main shaft 533 — the Sensor of speed of a secondary shaft 535 — ATF temperature Sensor 537 — the Switch of the Sport mode 540 — the Combination of devices	541 — SID 632 — the TWICE Control unit S1-S5 — Em switching valves transfers 1-5 SLS — (SL) of Em the coupling pressure valve SLT — (ST) of Em pressure valve in system SLU — Ø/m blocking valve Trionic — ECM (430/600)

During a start of motion 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, hydraulic or electronic control units. Hydrodriving disk brakes and disk coupling are applied to transition to other transfer relation in a planetary reducer.

Scheme of hydraulic management of AT

The torque converter on the functions corresponds to hydraulic coupling. Its task includes implementation of coupling at a start of motion and gear shifting. The hydrotransformer is equipped with the blocking coupling which is carrying out direct coupling of the engine with AT:

On AT AF33-5 – on 3-5 transfers (on petrol V6 engines – only on 4 and 5 transfers)
On AT AF30 – on 3 and 4 transfers.

Thus on AT AF33-5 the movement on the 3rd transfer with the included blocking instead of the 4th transfer without blocking, and on AT AF30 – on the 2nd transfer with the included blocking instead of the 3rd transfer without blocking is possible. Besides, the blocking coupling of the AT AF33-5 hydrotransformer at slow acceleration can slip, allowing a difference of turns of a bent shaft and main shaft AT within 50 ÷ 200 rpm. It allows to switch off the lowering transfer later.

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 other the mode of functioning of AT. Besides, it is possible to correct work of AT manually, choosing between the sports, winter or normal mode (see the Head Governing bodies and methods of operation). At failure detection in memory of the control unit the corresponding code registers (see Systems of electric equipment of the engine).

The only procedure of service of AT which implementation has to be made on a regular basis is replacement of its working liquid (ATF) and check of the ATF level which order of performance is stated in the Head Nastroyki and routine maintenance of the car.

Near a radiator of the cooling system of the engine ATF cooler is established.

Thanks to application of D/V of the modes "P"/" N" 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.