Reconditioned Alfa Romeo 159 Gearbox

Alfa Romeo 159 from 2005 to 2011: two engines, two very different replacement scenarios

The choice between an exchange unit and having your own gearbox rebuilt depends above all on the availability of original parts and the condition of the gearbox to be replaced. On the 159, this question plays out differently depending on whether you have the 1.9 JTDm or the 2.2 JTS: the diesel accounts for the vast majority of vehicles on the road and the bulk of demand, while the petrol remains a considerably rarer engine. When the gearbox of a 2.2 JTS (code 939A5.000) is still mechanically serviceable but has a partial fault, entrusting your own unit for reconditioning avoids having to track down a compatible core on a thinly supplied market.

1.9 JTDm: two engine codes, one identification pitfall to watch out for

The 1.9 JTDm fitted to the 159 comes in two distinct engine codes — 937A5000 and 939A2000 — reflecting engine revisions made between 2005 and 2011. These two codes do not necessarily share the same gearbox: before ordering, it is essential to check the code stamped on the block rather than relying solely on the engine capacity or quoted power output. Both engines use a 6-speed manual gearbox, but the internal references differ. A mix-up at this stage will result in a fitment incompatibility.

Common symptoms and wear patterns on this model

On the 159, 6-speed manual gearboxes typically develop difficulty selecting the lower gears (1st, 2nd) at high mileage, most often due to synchromesh wear. A dull rumble on cold rotation, or imprecise selection at the lever, points to an internal fault rather than an issue with the gear linkage. When these symptoms appear gradually, there is generally enough time to assess whether the existing gearbox is a good candidate for rebuilding rather than outright replacement.