GMC Brigadier

In 1966, General Motors split its heavy-duty trucks further apart from medium-duty models, giving them a distinct chassis and ending the use of the cab from the C/K-series pickup truck. The 1966 H/J-series (H=single; J=tandem) was designed with a model-specific 93-inch BBC cab and chassis. Alongside GMC V6 and Chevrolet 427 V8 gasoline engines, the H/J trucks were available with Cummins, Detroit Diesel, and Caterpillar diesel engines.[2][4]

The H/J-Series formed the basis of the C(later N)/M-series trucks; using a longer 114-inch BBC to accommodate larger diesel engines). In 1977, the N/M-series was replaced by the Class 8 Chevrolet Bison/GMC General semitractor. From 1966 to 1970, GMC would use a separate conventional school bus chassis from Chevrolet, basing it on the H6500 instead of the medium-duty Chevrolet C60 (in 1971, GMC would return to a medium-duty chassis).

GMC Brigadier semitractor

In the mid-1970s, General Motors began shifting away from its alphanumeric nomenclature for truck names. While still using the H/J name internally, the redesign brought new names to the vehicles. Chevrolet rebranded the H/J series as the Chevrolet Bruin, adopting a range of "frontier" nameplates for its truck range (Bison, Bruin, Kodiak, Blazer, Silverado, Scottsdale, Cheyenne). For its heavy trucks, GMC adopted a military-related nomenclature, with the H/J series becoming the Brigadier, joining the General and TopKick (a slang term).

GMC introduced the Brigadier in a 9500 series; an 8000 series was introduced for 1979. Chevrolet offered the Bruin in 70, 80, and 90-series. While tilting-hood examples are nearly identical between brands, butterfly-hood versions are distinguished by their headlight configurations (Bruins have two headlights; Brigadiers have four[5]).

1980s GMC Brigadier in use as fire engine

Following the launch of the product line, the GMC Brigadier quickly overtook the Chevrolet Bruin in sales and market share. After the 1981 model year, General Motors ended sales of heavy trucks by the Chevrolet Division, leading to the cancellation of the Chevrolet Bruin, Bison, and Titan. A major factor leading to the cancellation was lack of product support by Chevrolet dealers.

In contrast to Chevrolet (and other General Motors brands), GMC required all franchisees to sell and service the GMC product line in its entirety. In addition to light trucks, this meant a potential GMC franchise needed the ability to support medium-duty trucks, heavy-duty commercial trucks, P-chassis, the GMC Motorhome, and all bus chassis. For a GMC dealership, this requirement meant dedicating profitable space that would have otherwise gone to selling passenger cars.

In 1986, Volvo AB entered into a joint venture with General Motors in heavy-truck production, with Volvo holding an 85% stake.[6] To reflect the 1980 acquisition of White Motor Company by Volvo, the products of Volvo GM Heavy Truck Corporation were marketed under the combined WhiteGMC product nomenclature. While the slow-selling GMC General and Astro were discontinued, Volvo GM initially continued production of the Brigadier.

For 1988 production, Volvo GM re-released the Brigadier as a WhiteGMC (the only GMC truck produced under the joint venture). Along with revisions to the badging, a sloped hood became an option (sharing its grille with the GMC TopKick).[3] The WhiteGMC Brigadier was produced through the end of the 1989 model year, marking the retirement of the GM H/J chassis after 23 years.[3] For WhiteGMC, the role of the short-hood Class 8 conventional was adopted by the WG series, slotted below the WIL/WCL (replacing the GMC General); all WhiteGMC conventionals were evolutions of the White Road Boss series.

For 1990, General Motors redesigned its medium-duty C/K trucks for the first time since 1973, adopting the Chevrolet Kodiak and GMC TopKick branding for the model lines. In 1997, the 8500-series TopKick was introduced, marking the first Class 8 truck produced by GM since 1989.[7]