In 1981, WZ-551 finished prototyping proof of concept designs, and the vehicle was an indigenous chassis based on the imported Mercedes-Benz 2060 truck.

[9][10] WZ-523 project was then refocused for export effort and did not enter large scale service with the People's Liberation Army (PLA).

In 1986, WZ-551 was confirmed by Central Military Commission as the future PLA wheeled platform, beating the internal competitor WZ-523.

Type 87 was fitted with gun-launched anti-tank missile and sophisticated fire control system, aiming to defeat Soviet T-72 and T-80 tanks.

However, budgetary constraint, insufficient industrial capacity, and lack of interest from the Chinese military shelved further development beyond the initial proof of concept works.

Due to the urgent need to meet the schedule, the GIAT 25-mm autocannon was airlifted to China, as opposed to delivery via cargo ships, the usual practice at the time.

Despite being used as a common chassis for many different platforms, the total number of vehicles of all types entering Chinese service is small due to its engine problem, and with the exception of the basic APC version, no other versions of ZSL-90 is known to be successfully exported due to the same reason.

[16] One distinct visual difference between WZ-551A and its predecessors is that for WZ-551 (Type 90) and WZ-523, there's a significant gap between the front axle and the rear pair of wheels.

[18] In 1997, Chinese military reinvested interest in the development of road-mobile assault gun due to the Third Taiwan Strait Crisis.

The weaponry includes eight TY-90 missiles, QJC-88 12.7 mm heavy machine gun and 2 sets of 4 smoke grenade dischargers.

Additionally, a light solid state 3-D passive phased array radar is added to the fire control system, just above the original electro-optical fire control system, providing the ADS with greater surveillance range.

[20] Specifications: Produced by Norinco, the WZ-551 (Type 90) first developed in 1980s and certified in 1990, but the Chinese military were not satisfied with its performance, and the design had to be modified into WZ-551A (ZSL-92) in 1994.

The driver and commander sit in the front, and the engine is in the middle, with the turret basket and the passengers compartment located in the rear.

The periscope for the gunner can be fitted with passive night-vision device, providing limited night combat capability.

The vehicle is fitted with modernized electronics system, including gunner thermal imaging sight, laser rangefinder, angle measurement sensor, and digital ballistic computer.

[18] The PTL-02 assault gun is fitted with Type 86 smoothbore cannon, capable of launching anti-tank guided missile.

The WZ-551 chassis is made of fully-welded steel plates, providing all around protection against small arms fire and shell splinters.

The steel-reinforced radial tire allows the vehicle to travel at reduced speeds for 100 km when punctured.

The vehicle has off-road capability and is fully amphibious with steerable propellers behind the rear wheels.