the 253 V8 only came with either three-speed column- or four-speed floor-mounted manual transmissions. The 307 V8 was only available with two-speed Powerglide automatic. This arrangement continued until the 307 stocks were exhausted, following which the 253 and 308 locally built V8 engines could then be ordered with any manual or automatic transmission across the range, excepting the Holden Brougham which was always specified as a 308 automatic. A new locally manufactured three-speed automatic transmission, the Tri-Matic, was introduced late in the life of the HT range, except on HT Brougham which retained the two-speed automatic Powerglide transmission. HG The HG series of July 1970 was a minor refinement of the existing formula, adopted as the marketing platform for the new three-speed automatic transmission option called Tri-Matic. The first of these locally made transmissions actually found their way into the last of the HT series cars. These transmissions were later criticised for unreliability and became colloquially known by dispondants, as the Traumatic. Only the HG Monaro GTS350 retained the Powerglide transmission if an automatic preference was optioned. HG commercial variants continued to be built and sold alongside the HQ series passenger vehicles until very late in 1971 when the HQ commercials were released. These HG commercials were upgraded to the newer specification HQ 173ci and 202ci 6cyl engines but retained the HG specification transmissions (cable kickdown 6cyl and V8 Trimatics and V8 M21 Saginaw) and V8 engines which are believed to have been stockpiled in sufficient quantity to cover expected requirements. These HG commercials can easily be identified by the A prefix on the chassis number appearing on the firewall and for vehicles built for sale inside Australia on the Safety Compliance Plate. Second generation (1971–1984) HQ The HQ series of 1971 was a completely new design, introducing larger capacity 173-cubic-inch (2.85 L) and 202-cubic-inch (3.3 L) six-cylinder engines, with the continued availability of 253-cubic-inch (4.2 L), 308-cubic-inch (5.0 L) Holden and 350-cubic-inch (5.7 L) Chevrolet V8 engines. HQ was the most radically engineered Holden since the introduction of the original 48-215 model of 23 years prior. It featured a perimeter frame and semi-monocoque (unibody) construction, and was the first full-size Holden to have coil spring rear suspension. As a cost-saving measure, HQ was only engineered for right-hand drive, hence it was not feasible to sell the car in left-hand drive markets. Thus Holden exports declined from 41,181 in 1973