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Wheel change
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Video Transmission
Video Gearbox-gripes
Video History 1
Video History 2
Video Var. Speed Gearbox 1
Video Var. Speed Gearbox 2
Video Var. Speed Gearbox 3
Video Var. Speed Gearbox 4
Video Var. Speed Gearbox 5
Video Light commercial veh.
Video Shift Possibilities
Video Gearshift Lever
Video Transmission (truck)
Video Ecosplit Gearbox
Video Gearshift (truck) 1
Video Gearshift (truck) 2
Video Truck Multi-axle Gearbox
Video Group/Splitter Gearb.
Video Gearbox Lubrication
Video Axilliary Drive
Video Retarder 1
Video Retarder 2
Video Retarder 3
Video Overdrive
Video Synchronising 1
Video Synchronising 2
Video Two-Shafts Gearbox
Video Gearbox (de)mounting 1
Video Gearbox (de)mounting 2
Video Front - Cross-engine
Video 3 Shafts (not coaxial)
Video Gear Shaft
Video Transmission Design
Video Tractive Power
Video Direct Shift Gearbox 1
Video Direct Shift Gearbox 2
Video Direct Shift Gearbox 3
Video Form. 1 Transmission
Video Motorcycle Gearbox

Video Transmission Ratio
Video Three-shafts Gearbox
Video Two-shafts Gearbox
Video Gear Spreading

Video Manual Gearbox 1
Video Manual Gearbox 2

          A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Group and Splitter Gearbox


An unloaded truck can manage, without problems and on a level road, with only four speeds using the gear lever positions 2, 4, 6, 8. Even if one considers the lower usable RPM range. However, what happens if trailers, loads and mountain roads come into play? If one then considers the even narrower RPM range for economic engine operation, even a truck which only operates on roads, is wisely equipped with 16 speeds.


There are four change-gates for eight forward gears. What looks the same as for the use in the motor car, is somewhat more technically and more demandingly executed. With the changing from 4th to 5th gear, the 2 speed gearbox of the downstream group transmission is mostly changed through air pressure. Thereby the red gear ratios, seen in the above figure 'group' are usable. At the same time - unnoticeably - the first gear is engaged. Both must harmonise, otherwise the engine overrevs or it causes noises from the gearbox.The pre-change group is normally operated through a small lever on the gear-shift. With this the next half-gear is reached, shown in red in the above figure 'splitting'. Thus one can still drive with a load and a trailer with eight gears the same as in a motor-car with six. However, should an incline be reached, - even on the motorway -, the next lowest half gear is extremely important in preventing the loss of too much momentum. Construction site vehicles exaggerate sometimes by using as many as 32 speeds. 06/09               Top of page               Index
2001-2015 Copyright programs, texts, animations, pictures: H. Huppertz - E-Mail
Translator: Don Leslie - Email:

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