Subaru TY75 / TY85 (Subaru manual)

Subaru's longitudinal manual transaxles — in the Impreza, WRX and Legacy.

The TY85 six-speed is the STI gearbox and the one people seek out: it was built for the rally programme, it is much stronger than the five-speed beside it, and it is a common swap into cars that never had one.

The five-speed's weakness is well known and specific: fifth gear and its bearing. On a modified car it is the first thing to go, producing a whine only in fifth or fifth jumping out under load. A gearbox that pops out of one gear is a fork or a worn hub rather than general wear.

The centre differential is inside the transmission, which is what makes these unlike any other manual here — a bind or a judder in tight turns is the centre diff or the tyres, not the gearbox, and mismatched tyre circumferences are a real mechanical fault mechanism on a Subaru rather than a wear question.

They take a specific Subaru gear oil, and the front differential shares the case with the gearbox while the rear does not — so a Subaru has two or three separate oils and getting them confused is a recurring and expensive mistake.