[David_Hayward (RIP)]

Thornton Tandem Company of 5128 Braden Street, Detroit produced conversions for GM since at least 1932, with four-wheel drive.The Thornton system used a ‘Thornton’ transfer or relay case mounted above the rear axles, that took the drive from the engine and then distributed it to banjo-type axles and thence to the wheels, using Rzeppa CV universal joints. There was also a two-speed system that provided for a total of eight forward and two reverse gears. The system was also available for turning a Chevrolet truck into a tractor-trailer combination for larger payloads. It was also used in Ford and Dodge chassis. In the UK Universal Power Drives Ltd of Perivale, Middlesex used Thornton components in their 'Unipower' conversions, for Ford, Dodge, etc. chassis.

The Canadian distributor was H.V. Welles Limited of Windsor, hence 'Welles-Thornton' nomenclature.