Audi

Audi compact for everyday use or quattro SUV: two uses, very different demands on the gearbox, engine and turbo

An A3 1.9 TDI covering 30 000 km a year in heavy urban traffic and a Q5 3.0 TDI quattro towing a trailer on the motorway do not place the same demands on their transmission. The gearbox of a front-wheel-drive compact absorbs repeated clutch cycles at low speed; that of a permanent four-wheel-drive SUV also has to cope with the stresses of the transfer case and the torque shocks of a large diesel engine. The vehicle's usage context is the first filter for identifying the right part, even before the engine code.

A range centred on the A3 and A4, but covering the full model line-up

The A3 accounts by far for the largest volume, ahead of the A4 and the TT. Gearboxes make up the most extensive family, followed by turbos and then bare engines. The transfer case applies only to specific quattro configurations. Available types range from the 5- or 6-speed manual to the DSG 6 or DSG 7, sold on an exchange basis or rebuilt from your own unit depending on the reference. DSG units are supplied without the mechatronic unit, with a new dual-clutch assembly.

The identification pitfall: model year, engine code and power output first

With Audi, the same engine capacity can conceal very different units. The 2.0 TDI, the most common engine in the range, comes in numerous power variants — 110, 120, 136, 140, 150, 163, 170, 177, 184, 190, 204 hp — each with distinct engine codes such as BKD, CAGA, CAGB, CAHA, CJCA, CUNA, DFBA among others, which are not interchangeable. The 2.0 TFSI also spans a wide spectrum, from codes AXX and BPY through to CJXA, CJXB and CJXC on the 280 to 310 hp versions. The 1.8 T, produced from 1996 to the late 2000s, covers codes such as AEB, AGU, AJQ, AUM, AUQ depending on power output (150 or 180 hp) and drivetrain (front-wheel drive or quattro). The turbo, a part frequently affected on TDI and TFSI units, is also referenced by engine code: the same commercial designation can correspond to different turbine geometries depending on the year of production and the engine build date.

For V6 engines — 3.0 TDI, 2.7 TDI, 3.2, 4.2 — fitted to the A6, Q5, Q7 and A8, codes such as ASB, BKN, BNG, CAPA, CCWA, BPP, BSG, AUK, BDB strictly determine compatibility with the reconditioned gearbox or bare engine. The quattro configuration introduces an additional constraint: the gearbox supplied must match the integrated rear differential or not, depending on the vehicle generation. Always check the engine code stamped on the block before placing any order.