Also known as: fs6r31a, fs6r31, nissan 6-speed manual
Nissan's six-speed rear-drive manual — the FS6R31A, in the 370Z and the Pathfinder R51.
⚑ The RS6F51 is not this gearbox, and the letters are what say so: FS is longitudinal, RS transverse. The front-drive six-speed of the Sentra SE-R Spec V and the Maxima has its own page here. A parts listing that says only Nissan 6-speed manual covers both, and they share nothing.
The FS6R31A is the one people modify, and its failure follows: third and fourth gear synchros under hard use, then the gears. A 370Z that grinds into third under load is at the end of its rating rather than badly maintained — the same story as the Tremec T-5 and the Aisin AY6.
Nissan's SynchroRev Match is a control feature, not a gearbox one. It blips the throttle on a downchange, and when it misbehaves the fault is the clutch position sensor or the switch, not the transmission — which is worth knowing because the symptom feels entirely mechanical.
It takes a specific Nissan gear oil, and a heavier conventional oil makes it notchy when cold. That symptom has now appeared on seven gearboxes in this catalogue across seven marques, and it is never the synchros.
Cars fitted with this gearbox
3 generations. Only where a source names the model and the generation together — a gearbox is documented as a product far more often than as a fitment, so this list is deliberately shorter than the truth.
Nissan
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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