Start with what the GMT360 is: a 5-door wagon / 5-door retractable-roof wagon (XUV) / 2-door convertible pickup truck (SSR) with 4.2 L GM Atlas engine, built from 2001 to 2009, in the decade of stability control, dual-clutch gearboxes and the first serious hybrids. What it meant takes a little longer.
The story
GMT 360 is a vehicle platform that was manufactured by General Motors from the 2002 through 2009 model years. Underpinning the third generation of GM mid-size SUVs, the GMT360 architecture replaced the pickup truck-derived GMT330 chassis introduced for 1983. Vehicles using the platform were produced as five-door SUVs, a retractable-roof wagon/SUV/truck, and a midsize hardtop convertible pickup truck. The GMT360 architecture is among the most widely rebranded GM platforms in modern history.
Alongside its adoption by each GM brand (except Cadillac, Hummer, Pontiac and Saturn), the SUV platform was additionally marketed by associated brand Isuzu. Following the closure of Oldsmobile after the 2004 model year, its version was adopted by the Buick and Saab brands. Retired after the 2009 model year, the platform was originally slated to be replaced by a successor body-on-frame SUV (codenamed GMT361), with GM instead replacing the GMT360 vehicles with the Theta platform and the long-wheelbase GMT370 replaced by the three-row Lambda platform (which also replaced all GM minivans). The last GMT360 vehicles were assembled on December 23, 2008.
What is underneath
The engine is 4.2 L GM Atlas engine; other versions carried different engines, listed in the specification table below. Drive goes through a 4L60-E/4L65-E 4-speed automatic. The wheelbase is 113 in (GMT 360) / 116 in (GMT 368) / 129 in (GMT 370/305). These are manufacturer figures carried by Wikipedia and Wikidata, not road-test measurements.
Its place in the line
In the GM (General Motors) line-up the GMT360 has a clear place: it replaced the GM GMT330 platform; it handed the line to the GM Theta platform (GMT360) / GM Lambda platform (GMT370); the factory was Moraine, Ohio. The cars a buyer would have weighed it against include the Honda Fit, the Citroën C3, the Hyundai Santa Fe. Nearby in the GM (General Motors) catalogue sit the 1955 Chevrolet and the 1957 Chevrolet.