The DSG code is indicated on the vehicle data sticker (see Introduction). In addition, identification data is also indicated on the DSG itself, at the top and bottom (see illustration 1.1): here "PRC" is the DSG code, "15.01.08" is the production date (january 15, 2008.), "14" is the factory code, "09:49" is the production time, and "0042" is the serial number.
1.1 Location of DSG "OAM" identification data
The main feature of DSG is the presence of two parallel clutches, which allows two gears to be selected at once (only one gear is engaged). Therefore, when shifting gears, time is spent only on disengaging one clutch and engaging the other. The moments of clutch switching during gear shifting overlap, which makes it possible to accelerate with virtually no interruption of the power flow, allowing fuel savings of 4 to 8%. Interruption of the power flow is the main disadvantage of traditional manual transmissions, automatic transmissions and continuously variable transmissions operating in manual mode.
The DSG "OAM" transmission is an improved version of the 6-speed DSG 02E transmission (see Part B). It uses two single-plate dry clutches. The kinematic diagram is shown in Figure 1.2. Torque from the engine is transmitted to the dual clutch via a dual-mass flywheel. As in a manual transmission, the gear ratios are formed by pairs of gears located on two input and three output shafts. All gears are cylindrical helical. Since two clutches are used, the input shaft is divided into two coaxial shafts: the central (I in illustration 1.3) and a hollow outer (A), i.e. the central shaft is located inside the hollow. The driven gears are on three shafts (1-3). The combined clutch is driven hydromechanically, with automatic control by commands from the electronic transmission control unit.
1.2 Torque transmission diagram
A1 Input shaft No.1
A2 Input shaft No.2
B1-B3 Output shaft No.1 - No.3
With Main Gear
K1 Clutch No.1
K2 Clutch No.2
M Engine
T1 Part DSG with odd gears
T2 Part DSG with even gears and reverse gear
1.3 DSG shafts "OAM"
A Outer input shaft
I Internal input shaft
1-3 Output shaft 1-3
For the transmission to work properly, it is extremely important to maintain the correct fluid level in it. The DSG "OAM" has two circuits of working fluids, each of which uses different working fluids. One circuit (And in illustration 1.4) — with transmission oil, and the other (B) — with the working fluid of the hydraulic control unit "Mechatronic". Both of these fluids are filled for the entire service life of the transmission, their checking and adjustment of the level are not provided. The correct level is achieved when replacing the transmission oil. The mode of periodic switching on of the hydraulic pump "V40T" is applied in accordance with the needs of the control system. In this mode, the hydraulic pump is switched on only when the pressure in the control unit "Mechatronic" falls below a certain value. Thus, for the block to function "Mechatronic" no need for continuous pump operation.
1.4 DSG "OAM" working fluid circuits
The main parts of the DSG are shown in Figure 1.5.
1.5 Main parts of DSG "0AM"
1 DSG breather cap
2 Transmission oil filler cap
3 Selector mechanism lever
4 Block breather cap 5
5 Control unit "Mechatronic"
6 Double Clutch
7 Splined shaft (until 11.2008) or flange shaft (since 11.2008)
8 Drain plug, 30 Nm
9 DSG "OAM"
The description of the transmission control and its modes is given in the Chapter "Controls and operating techniques". Gear shifting is carried out by means of hydraulic activation, with electronic control.
Repairing a transmission requires a lot of special equipment, so disassembling and assembling the transmission and its components should be entrusted to service station specialists who have the appropriate equipment.