Scania shifts gear
Page 17
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SCANIA has modified its five and 10-speed synchromesh, range change and splitter gearboxes, mainly to ease gearshifting.
Low-friction bushes are now fitted in the gear-box top covers which house the gear selector rods while the position of the gear lever in the P-cab has been moved forward and its mounting angle changed to make first gear less awkward to select.
The ratios of the five-speed G770 are unchanged but the 10speed splitter model derived from it has a new fourth gear ratio and substantially revised planetary splitter unit, and is now designated GS771.
The fourth gear ratio change, from 1.31:1 to 1.17:1, has the effect of widening the step between fourth and fifth main gears but this leads to the splitter model now being a genuine 10-speeder whereas fourth high and fifth low were so close on earlier models that the GS770 was effectively a nine-speed gearbox.
But another result of the altered ratio is that the gearshift pattern becomes unconventional with a shift from seven to eight requiring a full lever movement, eight to nine a full lever movement and a split, and nine to 10 another full lever movement. To help overcome any teething troubles drivers might have, Scania is fitting explanatory diagrams in new vehicles fitted with the GS771.
The new splitter planetary unit is 76mm (3in) shorter as a result of the use of cone type synchomesh in place of the previously used multi-plate type. Splitter engagement is further improved by the use of electro-pneumatic operation in place of cable and by the removal of a clutch interlock which sometimes would cause the clutch pedal to stick down and the splitter to be "beaten".
The 10-speed range-change Scania gearbox's reverse gear ratio has been lowered from 11.1:1 to 13.77:1 mainly to reduce clutch wear when reversing very slowly and its model designation is now GR871 • All Scanias delivered from early next year are likely to have the revised gearboxes.
Scania's computer-aided gearshifting system, full described in CM January 29, is now in production and being offered as an option in Finland and Sweden. There are no firm plans as yet for offering it on UK models.