Upward mobility

| November 03, 2005

Moving heavy freight uphill requires patience and practice to avoid drivetrain problems.

Among trucking’s trickiest maneuvers is starting a heavily loaded truck up a steep hill from a dead stop. It’s relatively common, something drivers might face every day, and the maneuver includes several possible mistakes that are easy to make and can cause serious damage to a truck – even a driveshaft sheared clean in two.

“The transmission might be the weaker link in the drivetrain,” says Schneider Equipment Purchasing Vice President Steve Duley. “You might twist the main shaft in the transmission, and when that happens you have to rebuild the unit. But now we’re getting to where we damage more differentials: most likely it would be a broken ring gear, and that means the gear set has to be replaced.”

“I’ve seen them snap driveshafts,” says owner-operator Robert Lyonaisse of Fat Bob’s Trucking in Manchester, N.H. “I’ve seen them rip the rear end shackles right off. I’ve seen them split differentials and rip them right off the housings. I’ve even seen them bend frames.”

All of these mishaps, save bent frames, disable the truck; it can’t be driven, and expenses for towing, repairs and down time run high.

With 33 years of trucking under his belt, Lyonaisse has been both a driver and mechanic, and he has detailed knowledge of starting a heavy load uphill: the forces at work, how to control them and what can happen if the driver makes even a tiny mistake.

“The diesel engines nowadays put out so much torque,” he says, “and that effect on the drive train is compounded by the heavy load, the steep hill and the start up.”

If you’re at 70,000+ pounds and you come to a stop on a steep incline, don’t despair. Getting that big rig rolling again can be treacherous, especially for inexperienced drivers, but there’s a simple procedure for doing it without mishap. Experienced drivers do it routinely. Doing it correctly just takes time and practice.

A short physics lesson might help to explain the tremendous forces that clash with each other when a heavily loaded truck starts out on a steep hill. One force is gravity, represented by weight and the hill. The opposing force is torque, the twisting power created when all those big diesel horses go to turning the drive shaft and subsequently the drive axles. Torque and gravity meet primarily at the clutch and also between tires and road surface. The driver uses the clutch, throttle and gears to apply torque in controlled and sufficient measures to overcome the gravity and move the load up the hill from a dead stop.

To be sure, technology is simplifying the procedure for doing this and decreasing risks. Automatic transmissions for big trucks make it as easy as taking your left foot off the brakes while gently applying throttle with your right foot. Even some standard-shift transmissions have built-in torque controls that protect drive trains from over stress. As well, motor carriers can spec their trucks to handle max-loaded start-ups on steep hills with fewer problems.

“We spec out our trucks with a transmission that has a good low gear,” Duley says. “They have a heavy-duty drive-line. The engines have good starting torque, and we have our drive train combinations – transmission, drive shaft and differential – balanced pretty well, so none of those three components gets more strain than the others.”

Duley also explained why today’s electronic engines are harder to stall out. “They have what’s called a synchronous governor,” he says. “It automatically adjusts the fuel feed to keep the engine at a specified rpm, usually 600.”

For example, if the engine is idling at 600 rpm and the air conditioner kicks in, the synchronous governor increases fuel to keep the idle at 600 rpm even with the added load.

“It’s the same way when you’re starting out with a lot of weight on,” Duley says. “As soon as the clutch starts to drag, the synchronous governor reacts quickly to increase fuel, all the way to full feed if necessary, to maintain that idle speed.”

Aha! This is easy. Now we can go sit around the truckstop, right?

Not so fast, driver. No matter how a max-loaded 18-wheeler starts from a dead stop on a steep incline, the clash between gravity and torque is intense: destructive violence on a large scale looking for the least chance to explode.

“It’s very dangerous,” says owner-operator Niko Polena of Pahrump, Nev. “It’s one of the most dangerous things.” To control the situation, learn the procedure – timing, touch, understanding a diesel engine and using the tools of your trade properly.

“The first thing you have to do is make sure you’re geared low enough,” Lyonaisse says. “Make sure you’re in a lower gear.” For Lyonaisse, this means second gear, but some drivers like to start out even lower.

“You just put it in the lowest gear you have,” says owner-operator John Parker of Kansas City, Mo., who also has 33 years of experience.

Which gear you choose depends on certain factors. How many gears do you have?

“I usually run 13, 15 and 18 speeds because I haul a lot of heavy stuff,” Lyonaisse says. He says even with a 10-speed he’d start out with second, but most drivers go with the lowest gear. Also factor in the incline’s steepness, the load’s weight, and the truck’s general characteristics.

“Years ago I was driving an old International with a bad clutch,” Parker says. “What I used to do is get out and put a chock behind the wheel.” Parker says this allowed him to get rolling up the hill “without worrying about rolling into the car behind me.”

You’re stopped on the incline. Your left foot is holding the clutch pedal, and your right foot is on the brake. For good measure you’ve turned your four-way flashers on and turned off the CB and other distractions. With the clutch in, you’ve worked the gearshift lever through the first three or four gears to familiarize yourself with their locations in the shift pattern. They’re often the same or similar from truck to truck, but trucks develop their own personality at the gearshift linkage more than any place else.

With the truck back in low gear, you’re ready for the next step; when you’re about to take off, resist the urge to rev up the engine. “The whole thing is to let the truck do the work for you,” says owner-operator Robert Wood of Amelia, W.V. “Ease up on the clutch until you feel it start to engage: just barely starting to pull. If you let the clutch out too far too fast, you’ll either stall or break something.”

At this point, professionalism, or the lack of it, is revealed, as you must perform three delicate actions almost simultaneously for a smooth, uneventful take-off up the hill. “Take your right foot off the brake, let the clutch out all the way and apply steady, light pressure to the throttle,” says Wood, who has 12 years of experience.

Easily said, much harder to do, and only expert, hands-on experience makes it possible.

“If you feel the transmission jumping around, that’s chattering, and you’re in too high a gear,” Lyonaisse says. “Just drop it down another gear.”

To drop down a gear, depress the clutch pedal. The truck is barely moving and has no momentum, so it will stop immediately. Just as quickly, gravity will start dragging the truck down the hill, so hit the brake pedal at the same time the clutch pedal goes in.
If you’re in traffic, impatient motorists might be right on your bumper, especially if you stop suddenly. Do not let the truck roll backwards. Also, concern yourself with safety, not with your popularity among other motorists. They will get annoyed. Professionalism demands that you focus on safely operating the truck.

“Looking foolish is OK,” Duley says. “Having the truck roll back and hit the car behind you is not OK. Besides, you’ll never see those people around you on the highway again, and if they wanted to be in front of you they should have got up earlier,” he says.

Get the lower gear and start out again – clutch and brake in, release clutch slowly, feel it start to grab, right foot off brake and lightly on the throttle; pull away.

The truck is rolling; once again, resist the urge to rev it up. “If I’m pulling a big hill, I’ll run the rpms up a little higher than I usually do,” Lyonaisse says. “On flat ground I shift at about 1,500 rpm, but on a hill I’ll shift at about 1,700.”

This is important for two reasons. First, if you jack the rpm up over 2,000 and then try to grab the next gear, the transmission will stop you because the engine speed is too high for lower gears. You’ll blow the shift and have to start over.

Also, revving the engine that high in a low gear wastes fuel and abuses the truck. “Keep in mind fuel economy and wear and tear on your equipment,” Wood says. “You never want to run your engine up 2,000 or 2,200 rpm. That’s ridiculous.”

“Know your truck,” Wood says, “Know your engine. Caterpillars and Cummins shift better about 1,700 or 1,800 rpm, while Detroits can shift between 1,400 and 1,500.”

“It might sound funny, but listen to the truck,” Wood says. “It will tell you when to shift.” If the engine reaches the top of its power band (the rpm range wherein maximum torque and horsepower occur), it changes,” Wood says. “You’ll feel it hesitate. That’s when you’ve maxed out your rpms, and you should have shifted long before that.”

The first shift is as tricky as the startup. It requires timing and touch that can only be learned, not taught. With the rpm between 1,500 and 1,700, you must perform five separate actions in very close sequence: let off the throttle, depress the clutch, up shift, release the clutch and lightly get back on the throttle. If the rpm is neither too high nor too low and your aim for the next gear is true, you’ll shift smoothly.

Past the first shift, you’re on your way. “After that, just run the gears,” Lyonaisse says.
If you miss the first shift, just start over. Make sure the truck does not roll backward. If you can’t work up through the gears, the worst that can happen is you’ll have to crawl up the hill in low. This is no crime, but it might motivate you to practice this procedure and get it right, and there are places to practice.

“Right across from the Flying J in Barstow, Calif., there’s a truckstop that’s down in a hole,” Lyonaisse says. “You have to climb out of there, and at the top there’s a stop sign, but you’re still on the hill.”

“My brother and I would sit and make bets,” Lyonaisse says. “You could always tell the rookies. They’d stall a half dozen times.”

Starting a max-loaded big rig from a dead stop on a steep incline, and doing it safely, is part of your job. You’ll learn to do it one way or another. The more quickly you master this tricky, potentially dangerous and expensive maneuver, the more quickly you’ll move past the “rookie” stage up the steep slope to expert professionalism.


Standard Procedure
When starting heavy loads on steep inclines from a dead stop, follow this procedure, which represents the combined knowledge of five truck drivers with a total of 87 years experience. There are variations, and what works best for you is what you should use. But the following steps will work, and with experience you might modify some of them.

Remember the unlisted steps that come before any procedure: stay calm, maintain professionalism and deliver the freight safely on time.
1) Prepare to focus. Turn off the CB and music.
2) Locate shifter positions for first, second, third and fourth gears.
3) Turn on four-way flashers.
4) Left foot holding clutch pedal down, right foot on brakes.
5) Engage first or second gear.
6) At take-off, do not rev the engine. Keep right foot on brake.
7) Ease clutch out.
8) When clutch starts to pull:
A) Release brakes.
B) Add light throttle pressure.
C) Let clutch out completely.
9) At 1,500 – 1,800 rpm, up shift quickly and smoothly.
A) If you miss the shift, go back to step four and try again.
B) Don’t let the truck roll backward.
10) Continue up shifting, climb the hill; keep engine rpm below 1,800 as you climb. u


Tricky Incline Starts
Two uphill starts to avoid are on slick pavement and from the shoulder of a highway.

Wet pavement can significantly increase the difficulty of starting a heavy load uphill from a dead stop.

“It’s according to what kind of tires you have,” says owner-operator John Parker from Kansas City, Mo. “Some tires are good on a wet road, and some aren’t. But most of the time, if you have a hard pull in the rain, it’s going to slip a little on you.”

A little slippage is no cause for alarm. But if the drive tires completely lose traction and start spinning during an uphill start with a heavy load, you have to stop and try again using a lower gear and a slower start.

A steep-hill start-up on an ice-slickened road is especially dangerous. Drivers who tackle such a task have special equipment, such as chains or studded tires, and experience. Without these, no driver should even try starting a steep-hill start-up on ice. Once a heavily loaded truck starts to slide backward down the hill, it’s hard to stop.

If you’re climbing a steep grade and need to pull over, get to the top first, because starting a heavy load on the highway shoulder from a dead stop on a steep incline is extraordinarily dangerous and will likely cause an accident.

If you must attempt such a maneuver, start on the shoulder and build up as much speed as possible before pulling out into traffic. Only pull out when there’s a big gap in traffic so the next vehicle up the hill will have time to switch lanes or slow down. Communicate on the CB radio and use four-way flashers so drivers in smaller vehicles and other truckers, themselves trying to get up the hill, can give you the room you’ll need. Sometimes drivers take the shoulder all the way up, but often this is not possible.

Be aware that when you do pull out into traffic, you will be seriously obstructing it.

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