The single torsion bar was mounted through the frame sides behind the rear axle and then attached by arms and links to the front side of the spring U-bolt plates. Axle flex was discontinued for the 1936 model year. Post-war the use of torsion bar front suspension was a defining feature of British Morris cars, starting with the Morris Minor of 1948, its larger Morris Oxford MO counterpart and the upmarket Morris Six MS, plus the Wolseley-badged upmarket variants of the latter two models. The designer of these cars, Alec Issigonis, was inspired by the Traction Avant's suspension, although the Morris cars were rear-wheel drive and used conventional leaf springs for their rear axles. The Minor used lever arm dampers with its torsion bars while the Oxford and the Six used innovative telescopic dampers. The Minor remained in production largely unchanged until 1972 and was replaced by the Morris Marina which also used the torsion bar-lever arm damper system for its front suspension—one of the last new cars worldwide to be introduced with the system and which remained in production until 1984. The Oxford/Six platform was developed through several revised series which used Issigonis' torsion bar system until 1959 when the new Farina Oxford was introduced using front suspension with coil springs, lower wishbones and lever arm dampers. The most famous American passenger car application was the Chrysler system used beginning with the 1957 model year in cars such as the Imperial Crown series, although Chrysler's "Torsion-Air" suspension was only for the front; the same basic system (longitudinal mounting) was maintained until the 1981 introduction of the K-car. A reengineered torsion bar suspension, introduced with the 1976 Dodge Aspen, introduced transverse-mounted torsion bars (possibly based on the Volkswagen Type 3 passenger car) until production ended in 1989 (with Chrysler's M platform). Some generations of the Dodge Dakota and Durango used torsion bars on the front suspension. General Motors first used torsion bars on their light-duty pickup trucks in 1960 until it was phased out in 1963 where traditional coil springs are used up front for their 2WD trucks. Its first use in a passenger car was in 1966, starting with the E-platform vehicles (Oldsmobile Toronado, Cadillac Eldorado), 4WD S-10 pickups and Astro vans with optional AWD, and since 1988, full size trucks and SUVs with 4WD (GMT400, GMT800, and GMT900 series).