Audi

Audi A3 and Q5: two very different uses, one shared demand on the gearbox

A city-driven A3 endures hundreds of gear changes a day in heavy traffic; a Q5 or A4 on the road swallows motorway miles under load. These two wear profiles attack different components and lead to different failures. Within the Audi collection, gearboxes account for the vast majority of references, ahead of bare engines and a transfer case. The A3 alone makes up the bulk of the catalogue, followed by the A4, TT, A1 and S3 — models that sometimes share the same engine families or gearbox families, but not always the same part.

5- or 6-speed manual, S tronic, DSG: very different architectures depending on the year

The catalogue covers vehicles from 1996 to 2024, spanning several generations of transmissions. 5-speed manual gearboxes are found mainly on first-generation diesel engines — 1.9 TDI engine codes AFN, AVG, AHF — on A3 and A4 models from 1996 to 2004. 6-speed manuals take over with the 2.0 TDI and 1.8–2.0 TFSI units of later generations. The S tronic 6 and S tronic 7 dual-clutch gearboxes, as well as DSG 6 and DSG 7, appear on the sportier or four-wheel-drive versions: S3, TT, Q3, Q5. These DSG and S tronic gearboxes are supplied without the mechatronic unit, with a new dual-clutch assembly — a critical point to check before placing any order.

Identifying the right part: the engine code is essential

The same 2.0 TDI can correspond to engine codes as different as CAYC, CAGA, CLHA or CRKB, each of which may require a different gearbox or bare engine. The same logic applies on the petrol side: the 1.4 TFSI covers codes CBZA, CBZB, CJZA and CJXC depending on the generation and power output. Without the engine code stamped on the block, identification by engine capacity alone is insufficient and frequently leads to an incorrect reference. This four-letter code is visible on the side of the block, on the gearbox side. Diesel engines range from the 1.6 TDI to the 3.0 TDI, and petrol units from the 1.2 TFSI to the 4.2, reflecting the breadth of the Audi range covered — from the compact urban A1 to the Q7.