A dog leg gearbox is a manual transmission layout with an up-over-up shift between first and second gear.[1] The layout derives its name from a dog's hind leg, with its sharp angles.
| Dog leg 5-speed layout | Typical 5-speed layout |
|---|---|
Dog leg layout gearboxes are desirable on performance automobiles because in road racing more frequent shifting occurs from second to third than from first to second gear.
Examples of cars that utilized this pattern for performance reasons include the BMW M535, Early 635CSi (Non-US) and (Non-US) M3 E30, BMW 2002 Tii and Turbo, Mercedes-Benz 190E 2.3-16 and 2.5-16, Ferrari 308 GTB/GTS, Ferrari Testarossa, Porsche 914, early 911, 924 Turbo (all featuring Getrag gearboxes), Cosworth Vega, Porsche 928, Talbot Sunbeam Lotus, Vauxhall Firenza HPF the Lamborghini Miura, the Maserati Biturbo and the De Tomaso Pantera.
Despite the performance benefits, non-performance oriented cars available with the dog leg shift pattern were produced. Examples include the Subaru 360, Datsun 160J Hardtop SSS, 78-80 Datsun 200sx, 1980 Datsun 210 Wagon (built during the 210/310 crossover), 78-80 Datsun 510, Citroën 2CV, Mercedes 190, Mercedes-Benz 200D and the 1976-77 Oldsmobile Cutlass or Pontiac LeMans with the 260 V8, the 76-77 Chevrolet Vega or Pontiac Astre, 76-79 Chevrolet Monza or Buick Skyhawk or Oldsmobile Starfire, and the 77-79 Pontiac Sunbird.
Many light trucks have dog-leg 5 or 6 speed transmissions, due to the fact that second gear is fine for taking off normally, first is considered a crawler gear in these trucks and is only ever used for taking off with heavy loads and/or a trailer, or going down very steep grades.
The dog leg gearbox is also typical of 9 and 10 speed heavy truck transmissions. In the case of a 10 speed transmission, the gears are 1-5 in the low range and 6-10 in the high range (the 1 position is not used in the high range of a 9 speed transmission).