Building on that homespun phrase, Sloan said: 'In the past, all automobiles have been stiff-jointed. The front wheels, joined by a heavy I-beam and axle and stiff front springs, have communicated every jar and jolt to each other and to the chassis. In the new system, the old type front axle and springs are gone. Each front wheel is attached to the chassis by its own soft spring. The wheel, not the passenger, gets the jar.'
Naturally, GM called its innovation 'knee action.' It was one of several significant engineering developments during the Depression years.
Also in 1933, GM introduced no-draft ventilation. Remember the individually controlled vents in the forward sections of the front windows?
Hydraulic brakes replaced mechanical brakes in the 1930s, and GM brought out its turret top on the 1935 Pontiac and Oldsmobile. It soon spread across the board at GM. The turret top was an all-steel roof; it replaced the imitation leather section that extended the length of the passenger compartment.
Said GM in a 1935 ad in Automotive Daily News, 'it puts over your head a protection hitherto missing in all closed cars.'
Turn signals, which were developed by GM's Guide Lamp Division, arrived in 1939, on Buicks.
On 1939 models, Packard moved the gearshift lever to the steering column, thereby eliminating bruised knees for the middle passenger in the front seat.
In the fall of 1938, Chrysler offered Fluid Drive, a semiautomatic transmission, on its top-of-the-line 1939 Imperial Custom. But even bigger transmission news was about a year away.