Caterpillar CT 630

Australia's tipper industry has simple tastes, their requirements are for a good solid dependable truck, normally with a North American driveline and, in most cases, with a manual Roadranger. When the Caterpillar truck range first came out, it seemed to be ideally suited to the kind of vocational work which has, historically, been dominated by no-nonsense North American trucks like the Ford Louisville, Sterling and Mack.

Demographic changes in the tipping industry are beginning to push specification alterations into the truck buying decisions of many fleets. The average age of drivers in many of the larger tipper fleets is even higher than in the general truck driver population. The industry is desperate to attract new and younger drivers into the business. However, this younger group of drivers is much less adept at handling the skill set required to get the most out of a Roadranger box. Older drivers cut their teeth on trucks with engines with less power and a narrower torque band and, consequently, have developed a high level of skill in getting the best out of an unsophisticated constant mesh gearbox.

With more and more younger drivers being brought into the fleet, tipper operators are taking the auto option, when it comes to choosing gearboxes. Eaton's Ultrashift Plus is emerging as the automated option that can live with a North American driveline and get the job done. Caterpillar is now offering its current range with an Ultrashift Plus option, which had been unavailable when the first models came out.

Prime Mover took the opportunity to try out the C 15 powered Cat CT 630 with a loaded tipper and dog to see how it handled the climb out of the west of Sydney, up and over the Blue Mountains. The route saw the trucks heading west through Penrith, over the top of Mt Victoria, before turning around at Lithgow and returning to the NSW capital.

Climbing into the cab, the driver finds the well-known, simple layout associated with Cat and in place of the Roadranger stick there is a Cobra controller for the Ultrashift. This really is a no-nonsense truck and well-equipped to handle the rough-and-tumble of the tipper game. The instrumentation is simple and straightforward and all of the controls are available close to hand. Noise levels are relatively high, common for North American trucks, but may be reduced when the new ADR 80/03 C 15 engine is introduced over the next year or so.

The overall cabin design is quite smart. It was originally designed for the Pro Star International in the US market and has been adapted for our needs here in Australia. Visibility is good all round the truck and the driver position and windows have been located to maximise this. Cat has started with good basic design and we can expect the company to develop new designs on this solid base to cater for wider industry tastes over time.

One of the other issues common in North American trucks is not having enough room for the left foot in a footwell originally designed for the passenger side of the vehicle. With the Ultrashift in place, the issue goes away as there is no need for the clutch and plenty of room to place the left foot.
The performance of the C 15 engine is familiar, it has been around for quite a while and remains relatively unchanged. The low-down torque and the easy way it works to get the 40 odd tonnes of truck and dog up to highway speed makes for relaxing driving. The driver gets the feeling there is always plenty of power and torque available to get the job done without having to push the truck too hard.

Eaton has done a good job of matching the automated manual transmission program both to Australian conditions and the individual engines behind which it has been fitted. The Cat does have considerably different characteristics to its other North American rivals and, as such, needs to be treated differently. The improved level of information being used by the gearbox as well as its swift changes sees this gearbox as a quantum leap improvement over its Autoshift predecessor.

The gearbox does not change at the same point on the tachometer all of the time. It is clearly taking notice of accelerator pedal position, road speed, torque and whether the truck is ascending or descending a grade. It is carefully picking just the right moment in which to change gear to get the rpm levels right in the middle of the sweet spot and get the best out of the engine for the work it is doing.

The Ultrashift Plus transmission has introduced something for operators who prefer or need a North American driveline and also want an automated manual transmission which is comparable to the AMTs available in European trucks over the past 10 years. Its development was necessary for Eaton to claw back sales it may have lost as operators wanted to specify an AMT but were looking for an effective and productive two pedal box.

The way the Ultrashift works is very intuitive, it picks up on changes when they need to be made at the same time or just before an experienced driver will be looking for the change. The ratio changes are smooth and swift and there's only a short period during which the driveline is disengaged. Every upshift uses the clutch whereas all of the downshifting is done without a clutch and the transmission control simply modulates engine rpm to slot the next gear home.

When holding a fully loaded truck on a hill, the Ultrashift system acts just like a driver and simulates something like the slipping of the clutch required to take off smoothly. The system knows the truck is on a slope and also knows the driver is wanting to take off. It's possible for the driver to modulate the clutch by increasing and decreasing pressure on the accelerator with the right foot. The system also tells the driver when they are overdoing this. A sensor within a gearbox and at the flywheel keeps an eye on the situation and if the driver is overdoing the clutch slipping, the letters CA (for clutch abuse) appear on the gearbox indicator in the dash.

Another problem for drivers using the new auto gearboxes is remembering to put the transmission back into neutral when pulling up. It's very easy to stop the truck, pull on the handbrake, then jump out. The way Ultrashift overcomes this is to select neutral as soon as the maxi brakes are activated. When the driver comes to start the truck again or set off, the transmission is in neutral but the selector is still in drive. The system will not allow the driver to restart the truck without putting the selector into neutral, synching it with the situation within the box.

The way the transmission control system has been calibrated sets a number of strict parameters which underline the required performance of the transmission. For example, Ultrashift Plus will not let the rpm levels drop below 1100rpm. When changing up a gear, the control system takes into account road speed, road inclination and engine rpm to ensure that when the shift is made, the engine will be running at above 1100rpm.

Coming down a grade can be problematic if the AMT is not set up just right to deal with the control of engine brake, gear ratio and road speed. The way this box handles was shown when coming off the top of Mt Victoria – it's simply a matter of putting the transmission controller into Low position and waiting for the Ultrashift to start grabbing gears to get the engine rpm levels high enough to improve the effectiveness of the engine brake. Once the system has found a gear which allows the truck to comfortably descend the grade just using the engine brake, and perhaps the occasional service brake application, it's simply a matter of putting the transmission control into Manual and descending the grade under full control.

One of the issues with the first batch of Ultrashift Plus transmissions which came into Australia was a certain lack of precise and subtle control when manoeuvring the truck at slow speeds. There was a tendency of the clutch to grab when attempting tasks like reversing a prime mover under a trailer or reversing onto a loading dock. The programming has been reprogrammed considerably and by activating the Low position on the gearbox controller the driver has a lot of accelerator movement to play with before there is any movement by the truck. The slow manoeuvering control has seen changes in the way the clutch is actuated by the transmission but also an amendment to the engine control software within the engine control module.
Entering the Australian truck market was always going to be problematic for Caterpillar, as it is for any new brand. They were able to launch two models with very few specification options. Now, 18 months down the track, the first real options are coming on stream and we can expect this auto introduction to be followed by a number of additions and changes in the Cat offering to the market as the company starts to spread its wings.


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