Ford 6F35

Ford's smaller six-speed automatic for transverse engines, in production since 2009 and fitted to the four-cylinder Fords and Lincolns — the Escape and Kuga, the Focus and C-Max, the Fusion and Mondeo, the EcoSport, and the 2.0-litre versions of cars whose V6s got something bigger.

It is the small half of a range, and the distinction runs right through this catalogue. Ford's transverse six-speeds come in two sizes: the 6F50 for the larger engines, and this one below it. GM built the same two sizes as the 6T70 and the 6T40, because the whole programme was a joint one begun in 2002. So there are four pages here for what is often loosely called one gearbox — two makers, two sizes.

And they are genuinely four things rather than four names. The clearest statement of it comes from the trade: the 6F35 and the GM 6T40 look alike, but interchanging components between them is close to impossible. A shared programme produced shared architecture and almost no shared parts, which is precisely why this catalogue declines to alias any of the four into any other.

There are two generations of this unit and 2012 is the line. The earlier ones carry the family's inherited weakness; the later ones were substantially revised.

That weakness is the same one its three relatives have: the spring disc in the 3-5-R drum. Third, fifth and reverse depend on it, and on units built before about 2012 it cracks. Four pages on this site now name that part — GM's two and Ford's two — which is what a shared design should look like when the sharing is real.

What else the trade meets, and the first item is where the chain starts:

• Rapid wear of the torque converter's lock-up clutch, which is the source of the debris in everything below it.
• A valve body clogged by that debris, and the loss of controlled pressure that follows.
• The differential housing's bearing hub, which deteriorates and is a more serious repair than it sounds, because of what it sits in.
• The solenoid harness, which is short-lived, and speed sensors that fail through contamination — both electrical faults that present as mechanical ones.
• Sliding bushing wear, and a cooling system the trade considers weak for the work the unit is asked to do.

On fluid: Mercon LV, around eight and a half litres, on an interval near 60,000 km. The argument is the sequence above rather than the schedule: the lock-up clutch will shed material whatever an owner does, and the fluid is the only thing between that material and the valve body.