Actually, Dexron III/Mercon is not recommended for use in transmission servicing in Type "D" applications. Type "D" is the original Dexron formula and is still made specifically for Nissan. Dexron III has a thicker viscosity than Dexron/Dexron II and has been found to cause sticking inside the transmission valve body; Nissan released a TSB on the issue. Dexron III is safe to "top-off" the fluid level, but for a trans service, it's best to stick with genuine Nissan Type "D" ATF or an aftermarket ATF that is "recommended" for use in Dexron II applications. Those would include Valvoline Maxlife ATF, Castrol Multi-import ATF and Amsoil's ATF. Usual drain and fill is about 4-1/2 quarts (US).