In the late '80s, General Motors, together with Isuzu and Honda, worked on a badge-engineering project, and the Opel Monterey was one of the products.
While GM delivered the chassis, Honda came with the V-6 gasoline engine, Isuzu brought the turbo-diesel versions, and GM delivered the chassis. At that time, the American carmaker held one-third of Isuzu's stocks and already had other agreements with the Japanese company. In Europe, GM had two brands: Opel for the continental side and Vauxhall in the U.K.
GM designed the two-box design of the big Opel Monterey, and it was similar to the Acura SLX and Isuzu Trooper. The car featured body-on-frame construction, with a low-range gear fit for off-road. Its front fascia featured squared headlights with corner-mounted turn signals and a rectangular, chromed surrounding for the grille, which sported the Opel lettering. It was unusual for the German brand to place its name, not its badge, at the car's front. The design team made a tall greenhouse with a simple design and a thicker C-pillar, while the doors featured grab-handles. Despite the car's length, the Monterey had its spare wheel mounted on the tailgate in the back.
Inside, the base model featured cloth upholstery, while the upper trim level received leather. The instrument cluster featured the same layout as Isuzu or Honda, with six gauges and the tachometer and speedometer larger than any other gauge, with the automatic transmission indicators.
Under the hood, the carmaker offered the Monterey a choice of two engines: a 3.2-liter carried over from Honda and a 3.1-liter turbo-diesel made by Isuzu.