It's a Canadian thing.
Homer
Probably Maint 3 = Preferred Maint
"PREFERRED MAINTENANCE* (Every 6,000 kilometres or 3 months, whichever comes first)
Preferred Maintenance is a Nissan-recommended option that is suitable for all driving habits and local conditions. Nissan developed Preferred Maintenance for owners who want the ultimate in preventative maintenance. With Preferred Maintenance, more maintenance items are regularly checked or replaced than with either Schedule 1 or Schedule 2 maintenance schedules. Using the Preferred Maintenance schedule may optimize the performance, reliability and resale value of your vehicle.
Replace engine oil and filter
· Lubricate propeller shaft 1
· Replace automatic transmission/CVT fluid
· Replace engine air filter
· Replace engine coolant/flush system
· Replace engine drive belts
· Replace free-running hub grease 2
· Replace front wheel bearing grease (4WD only)
· Replace fuel filter 3
· Replace in-cabin microfilter 4
· Replace limited-slip differential oil 5
· Replace manual transmission oil
· Replace PCV filter (4 cylinder Frontier/Xterra)
· Replace radiator cap
· Replace wiper blades
· Rotate tires (except 350Z)
· Optional: flush automatic transmission (flush with ATF)
· Inspect the following:
__ All lights
__ Axle & suspension parts
__ Brake lines & cables
__ Brake pads, rotors, drums & linings
__ Drive shaft boots
__ Exhaust system
__ Front suspension ball joints
__ Front wheel bearing grease (2WD only)3
__ Fuel lines/connections
__ Fuel tank vapor vent system hoses
__ Headlights/adjust if necessary
__ Propeller shaft (4WD/AWD)
__ Steering gear and linkage
__ Steering linkage ball joints
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1 4WD version of Frontier, Pathfinder, Xterra. (Propeller shaft should be re-greased after being immersed in water).
2 4WD versions of Frontier, Xterra.
3 Frontier, Pathfinder, Xterra.
4 Standard equipment on Maxima, Murano, Altima, X-Trail, Quest SL, SE, Titan Crew Cab LE, SE. Optional acccessory on all other models.
5 350Z, Frontier, Pathfinder, Xterra, AWD Murano, Armada, Titan, AWD X-Trail.
6 Replace (not just inspect) oil/fluid if towing a trailer, using a camper or a car-top carrier, or driving on rough or muddy roads