Manual Transmission Fluid

Use genuine Honda MTF and nothing else. This is the single most repeated piece of advice in the S2000 community and it is repeated for a reason. Standard GL-5 gear oil attacks the yellow metal in the synchros, and the S2000 gearbox is unusually sensitive to it. A grinding second gear synchro is the usual symptom, and it does not heal.

Honda's underlying figure is 1.56 US qt (1.48 L), which every owner's manual rounds to 1.6 US qt (1.5 L) for a change, with 1.7 US qt (1.6 L) as the total. The 1.7 figure that circulates online is that total, quoted in the service summary of the 2004 to 2009 manuals. Fill to the bottom edge of the filler hole rather than trusting a number.

The interval is not one number across the run. The 2000 and 2001 schedule calls for a change at 90,000 miles or 6 years. From 2002 the fixed schedule moves it to 120,000 miles, and 2006 onward cars have no mileage figure at all: the fluid is changed when Maintenance Minder sub code 3 appears.

Honda's published interval is far longer than common practice. Most owners change it around 30,000 miles. That is a community habit rather than a requirement, though this gearbox is known to be sensitive to fluid condition.

Capacities checked against all ten owner's manuals, 2000 to 2009, and Honda's specification sheets. Intervals checked against Honda Owners Site maintenance schedules for 2001, 2002 and 2007 to 2009.