Peugeot PSA MB6 / ML6

PSA's six-speed manual transaxle — in the Peugeot 508, and, since Stellantis, in the Opel Astra K and Corsa F.

An Opel with a PSA gearbox is what the 2017 acquisition left behind, and it splits the useful literature between two marques that had nothing to do with each other before: a Corsa owner and a 508 owner are researching the same transaxle.

Its recurring complaint is shift quality rather than failure. The cables, their end bushings and the lever's own base wear, producing a change that is long, vague, or refuses reverse — and reverse is where it shows first, because it has no synchro to cover an imprecise selection.

Where it wears inside it is the second-gear synchro, crunching on a fast cold change and nowhere else. A crunch in every gear is the clutch not releasing — hydraulic, outside the gearbox, and much cheaper to put right.

The clutch's slave cylinder is concentric on most applications, inside the bellhousing, so it is worth replacing whenever the gearbox is out regardless of its condition.