The Toyota Hilux pickup (upon which the Surf was originally based) underwent a major redesign in 1983 for the 1984 model year. Instead of developing an entirely new model, Toyota took an existing short-bed pickup body, made some simple modifications, and added a removable fiberglass top.
Thus, the first generation Surf is nearly mechanically identical to the Toyota Hilux pickup. All first generation Surfs had two-doors and were indistinguishable from the pickups from the dashboard forward. Nearly all changes were to the latter half of the body; in fact, because the rear springs were actually downgraded with one leaf less than the pickup, with the additional weight of the rear seats and fiberglass top, these models tend to suffer from sagging rear suspensions (a problem which continued to afflict later generations of the Surf).
The first Surfs were introduced in 1984 as 1984 1/2 models. For this first year, all models were equipped with black or white fiberglass tops.
In 1986, the Surf underwent a major front suspension design change as it was changed from a solid front axle to the Hi-Trac independent front suspension. This change made the Surf more drivable at highway speeds and increased the space in the engine compartment (necessary to fit larger engines, such as the V6 introduced in 1988) but arguably decreased the truck's off-road capabilities. The Hilux at this point retained the more rugged and capable, if less refined, solid axle configuration
Small cosmetic and option changes were made in 1989, but the model was left largely untouched in lieu of the replacement model then undergoing final development.
The 1990 model year Surf continued its reliance on the Hilux pickup, as the pickup was redesigned the surf followed. It remained virtually identical to the Hilux from the 'B' pillars forward, but this time gained a full steel integrated body in place of the prior fiberglass cap. It also gained an all new coil sprung rear suspension system, which unfortunately proved to be just as prone to sagging as the leaf springs on the rear of the previous models.