The D21 generation was the successor to the Datsun 720 line of pickup trucks. They were called Nissan Hardbody Trucks in the United States
The truck's name, "Hardbody", refers to its double-wall bed and overall styling. The Hardbody was produced for the U.S. Market from 1986.5 until 1997, and were direct competition to the Toyota mini pickup. The old to new Nissan body style changed in mid-year 1986, so the new 'D21' 1986 Hardbody trucks are referred to as 1986.5; they can be distinguished from the earlier 720 body by their two large headlights rather than four smaller. The Nissan Pathfinder was derived from the Hardbody Truck and started in the same model year with chassis code WD21.
In the US, the Hardbody cab styles were 'Standard' and 'King' (also known as 'Extended'). Bed lengths were 'standard' 6-foot (2m) and 'long' seven foot. International markets also received the 'Crew Cab' (4-door) version with a short four and a half foot bed. Both 4-cylinder and V6 engines were available, with the 2.4L 4 cylinder KA24E being a respectable-performance SOHC engine that replaced the Z24i for 1990-1997. The 6 cylinder 3.0L VG30E engine increased power and torque only modestly (with 1995 being the last year the VG series engine was available until the replacement Frontier), and was not available on all the Hardbody variations. Five-speed, including overdrive, manual transmissions were the most common, but an automatic transmission was available for some configurations. Both rear wheel drive (4x2) and four wheel drive (4x4) versions were made in quantity. A limited slip differential was standard on the top 'SE' trim. Major options included air conditioning, larger wheels/tires, sliding rear window, radios, and rear bumper. There were several trims available including base, XE, and top of the line SE. The XE could be ordered with a 'value package' starting in 1994 which included air conditioning, power mirrors, alloy wheels, and chrome on body trim such as the mirrors and bumpers. The SE was better equipped and most came fully loaded from the factory with sunroof, power windows and locks, air conditioning and alloy wheels. A new more ergonomic dashboard arrived for 1994 replacing the previous angular design. A driver's side airbag was added for 1996 while rear wheel ABS came with both 2WD and 4WD models.
These low-cost, dependable Hardbody small pickup trucks sold very well worldwide, and are still often seen both on-road and off-road. They are renowned for their reliability and endurance, with the exception of body panel and frame rust over time. Other things to look for are a noisy timing chain on the 4 cylinder which may mean the timing chain guides or timing chain are worn. The V6 engine has a timing belt that requires replacing every 60 000 to 80 000 miles. Should the belt break, serious and costly engine damage is likely to occur due to the valvetrain's interference design. Exhaust manifold studs are also know to fail prematurely on the V6.
The D21 was replaced by the D22 which is being made in South Africa and elsewhere in the world.
This D21 design was still available new in some Latin American countries, made in Mexico until the 2008 model year. In its current home country a range of four basic variations of the D21 are sold together as the Nissan Camiones (literally "Nissan Trucks").
Nissan Mexicana ended production of the Camiones in March 15, 2008 after 15 years of production in the Cuernavaca plant.