Unusual four-wheel drive systems

Prompted by a perceived need for a simple, inexpensive all-terrain vehicle for oil exploration in North Africa, the French motor manufacturer Citroën developed the 2CV Sahara. Unlike other 4x4 vehicles which use a conventional transfer case to drive the front and rear axle, the Sahara had two engines, each independently driving a separate axle, with the rear engine facing backwards. The two throttles, clutches and gearchange mechanisms could be linked, so both 12 bhp 425 cc engines could run together, or they could be split and the car driven solely by either engine. Combined with twin fuel tanks and twin batteries (which could be set up to run either or both engines), the redundancy of two separate drive trains meant that they could make it back to civilization even after major mechanical failures. Only around 700 of these cars were built, and only 27 are known to exist today. Enthusiasts have built their own "new" Saharas, by rebuilding a 2CV and fitting the modified engine, gearbox and axle onto a new, strengthened chassis.

BMC experimented with a twin-engined Mini Moke in the mid-1960s, but never put it into production.

Suzuki Motors introduced the Suzuki Escudo Pikes Peak Edition in 1996. Though actual numbers were never released, this twin-engined vehicle is believed to weigh around 1760 pounds and produce nearly 1000bhp. The engine is a twin-turbo charged 2.0L V6 mated to a sequential 6-speed manual transmission.

Nissan Motors has developed a system called E4WD wherein the rear wheels in a car that is normally front-wheel drive are driven by electric motors. This system was introduced in some variants of the Nissan Cube and Tiida.

Most recently, DaimlerChrysler's Jeep Division debuted the twin engine, 670 hp Jeep Hurricane concept at the 2005 North American International Auto Show in Detroit. This vehicle has a unique "crab crawl" capability, which allows it to rotate in 360 degrees in place. It also has dual Hemi V8s.