Jatco JF015E

Jatco's CVT7, built from 2010 for small cars — the Nissan Note and March, the Mitsubishi Mirage and Lancer, the Suzuki Swift, the Lada Vesta and a long tail of others. It is rated to about 160 Nm, the smallest unit in this catalogue.

And it is the only transmission here with a gearbox inside its gearbox. A variator's ratio spread is limited by how large its cones can be, which on a cheap, compact unit is a real problem: you cannot have both a low enough ratio to pull a car away and a high enough one to let it cruise quietly. Jatco's answer was to put a two-speed planetary gearbox in series with the variator. The variator sweeps its range in low, the auxiliary box changes up, and the variator sweeps its range again.

The result is the number worth remembering: a ratio spread of roughly 4.0 to 0.55 — about 7.3 to 1 — from a unit rated for a 1.2-litre engine. That is wider than most six-speed automatics on this site manage, and no variator of this size could produce it alone.

It is still a CVT and this catalogue records no speed count for it, which is worth saying because this is the one unit where that looks wrong. Those two steps are internal; a driver never selects them and the ratio the car is actually running is continuously variable.

The auxiliary gearbox also brought a failure none of the other CVTs here have, and it is very specific: the sun gear cracks along its weld. That gear is what selects forward and reverse in the planetary section, so when it goes the car loses drive rather than merely shifting badly. Jatco thickened it in 2015, along with improved cone bearings, so the later units are a different proposition from the early ones.

The rest is the pushbelt family's usual list, arriving early:

• Cone wear and belt stretching from as little as 30,000–50,000 km, which is early even by CVT standards and is the price of a small variator working hard.
• Cone bearing wear, which announces itself as a hum that rises with road speed rather than with engine speed.
• The input shaft, described by the trade as the unit's soft spot, and the Teflon sealing rings on it — when those wear, the debris goes into the fluid and the fluid goes to the solenoids.
• Solenoids, which are as sensitive to contaminated fluid here as in every other Jatco unit.

The honest summary: the auxiliary gearbox is a clever answer to a real constraint and it bought this unit a ratio spread its variator could never have managed. It also added a part that can crack and take reverse with it. Fluid and heat remain what an owner controls — and on a unit whose cones are working this hard for their size, the interval matters more than it does on the bigger CVTs, not less.