Reconditioned Volkswagen Transporter 2.4 TDI Gearbox

2.4 TDI Transporter from 1990 to 2003: AAB or AJA — is the gearbox the same?

No. Engine codes AAB and AJA do not automatically correspond to the same gearbox, even though both power the T4 with the same 2.4 TDI. Checking the engine code stamped on the block is essential before selecting the correct gearbox reference to order.

What the gearbox references reveal on this T4 generation

The 2.4 TDI in the Transporter T4 is paired in all cases with a 5-speed manual, but the listed gearbox references — DKA, ARL, AYD, CRN, CRL, CLZ, CHS, CCY, AYF — are not freely interchangeable. Several families coexist across the 1990–2003 period, and a Transporter built early in the production run does not necessarily carry the same unit as a late T4. The engine code remains the essential starting point; the gearbox number stamped on the casing then confirms the exact family.

Known weaknesses of the 2.4 TDI under heavy commercial use

The 2.4 TDI is a robust engine, but the Transporter's typical usage profile — heavy loads, frequent starts, long distances — places particular strain on the 1st and 2nd gear synchromesh rings as well as the gearbox bearings. The most common early warning signs are difficulty engaging 1st gear when cold and bearing noise at a steady speed. Two reconditioning options are available depending on the condition of the original unit.