When the shift lever is in neutral, let up on clutch pedal. Note: Avoid depressing the clutch pedal too far and contacting the clutch brake.ģ. Depress clutch pedal slightly to break torque enough to move the shift lever to neutral. Use only for initial gear engagement when the vehicle is standing still.Ģ. Never use the Clutch Brake when upshifting or downshifting. It is a disc-type brake incorporated into the clutch and transmission drive gear assemblies. When applied the brake slows down and can stop the transmission front box gearing. (Used with pull-type clutches) – The clutch brake is applied by fully depressing the clutch pedal to the floor board. The HI range “L”/rearward position provides for 5th through to 8th gears the HI range ‘H’/forward position splits each of those speeds (providing 8 ratios in HI range) – that’s how 18 progressive ratios can be obtained. The LO range ‘L’/rearward position provides for LO through to 4th gears the LO range ‘H’/forward position splits each of those speeds (providing 10 ratios in LO range). When in LO or HI range, the ratios can be split by using the splitter control button. Preselecting all range shifts prevents damage to the transmission and provides for smoother shifts. After preselection, the transmission automatically makes the synchroniser range shift as the shift lever passes through neutral. Range ShiftĪlways preselect the range shift just before making the selection. It is used once during the upshift sequence and once during the downshift sequence. LO range and HI range are selected with the range lever, commonly located at the front of the gear selection knob. However, each of the five ratios (LO-1-2-3-4) in LO range, and each of the four ratios (5-6-7-8) in HI range can be split with the splitter gear giving a total of 18 different ratios.Īfter shifting out of the LO position, you use the common ‘H’ shift pattern. The other four ratios are used once in LO range and once again in HI range. The LO position in the front section is used only as a starting gear, it is never used when the transmission is in HI range. The auxiliary section contains LO and HI range ratios, plus a splitter gear. Models in this series provide eighteen forward speeds and four reverse, consisting of a five-speed front section and a four-speed auxiliary section. In this article we’ll be using the more modern and common 18-speed Roadranger in our example, however the principles described in article are transferable to other transmissions in Eaton’s Roadranger Fuller range. Roadranger transmissions are a constant mesh style transmission, which means that all the forward gears are constantly in mesh at all times. Jammin’ gears is not, and never has been, the method of how it’s done, although if you stand at a roundabout somewhere near a transport hub in any major city for half an hour, you’ll hear plenty of gears being jammed. Swapping gears properly in an Eaton Roadranger transmission is a skill that professional drivers pride themselves in. ![]() However, when Haggard mentioned “Jammin’ gears,” it was a slang reference to the time used to describe the action of changing gears in crash or constant-mesh gear boxes, which old seasoned truck drivers mastered, slipping each gear change through smoothly and silently without any grating sound. To a certain degree, his line: “Jammin’ gears has got to be a fever, ‘cause men become addicted to the grind,” is true for many drivers. That song became the theme song for the NBC-TV hit series Keep Movin’ On in the mid-seventies. When Merle Haggard penned the words to his famous single that paid homage to the truck driver, Movin-On, in 1975, he captured the real spirit of trucking that still holds true today: “The white line is the life line to the nation”. ![]() However, many believe that being able to change gears in an 18-speed Roadranger gearbox is still a skill worth mastering… Times have changed, roughly 50 percent of today’s trucks have auto boxes, and a driver’s ability to change gears in a manual transmission is no longer a prerequisite to becoming a truck driver. It’s worth remembering too, that those old trucks with the 13 and 15-speed Roadrangers were not as powerful as today’s trucks, which meant drivers were constantly required to change gears. Driving a constant mesh transmission like a 13-speed or 15-speed Roadranger transmission correctly used to be a fundamental part of truck driving, and old school truck drivers took great pride in the way they swapped cogs meticulously without grating any gears. How to drive an Eaton 18-Speed RoadrangerĮaton’s 18-Speed Roadranger Driver’s Instruction manual available for download at end of article.
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