“This rubber-tracked, articulated dozer is based on years of working with customers, and their interaction with our engineers,” says Scott Bayless, John Deere product consultant for the HSD. “It became apparent that as grade control and GPS was getting better and better, contractors were using dozers more and more for doing finish-grade work instead of motor graders. They were using GPS-enabled dozers but they were limited by their (steel-tracked dozers’) mobility.
“They wanted a machine that had the pushing power of a dozer, the finishing grade ability of a motor grader, plus the mobility of a motor grader or a machine as nimble as, say, a wheel loader.”
We asked the top dozer hand at the Union of Operating Engineers’ Local 150 in Wilmington, Ill., how well the 200-horsepower, 34,000-pound innovation delivers on that wish list.
Kevin “Zip” Ackert, a veteran dozer operator and instructor for Local 150’s Apprenticeship and Skill Improvement Program, met us at the Local’s facility in Wilmington with a day planned to resurface 1,000 feet of gravel road with recycled asphalt and to subject the 764HSD to some other challenges.
A 30-ton articulated truck dumped rough windrows of the ground asphalt on the road, and Ackert, in his first minutes at the HSD’s controls, set to work knocking down piles.
Last year’s introduction of the 764HSD (high-speed dozer) seems like the crowning evidence on several years of equipment buyers testifying to John Deere’s efforts to integrate the construction-equipment customer’s input into Moline’s product development business.
“When you look at the size of it, you wouldn’t think it’s as agile as it is,” Ackert says. [The machine is almost 23 feet long overall. Width over the tracks is 8 feet 6 inches, and the 11-foot blade is a direct lift from Deere’s 700J dozer.] “But you could just literally put it in reverse and back over it [the windrows].
The grindings were lumpy—about what you’d expect from donated materials.
“In a regular steel-tracked dozer, I’d have to go see the chiropractor at the end of the day,” Ackert says. “I could have worked with a conventional dozer to bring the rough material to grade, but it wouldn’t have been as fast.”
The 764HSD’s hydraulic suspension—a system on the front axle that uses accumulators similar to those in ride-control systems for wheel loaders, backhoe loaders and skid steers—turned out to be a back saver even when adjusted for a firm ride.
“The suspension, with accumulators, is just amazing,” Ackert attests. “What they [Deere] call for when running with GPS is for the system to be at full. It’s a fairly rigid ride, but it will still soak up a lot of unevenness compared to a rigid frame.”
Deere wanted to deliver a real leap in productivity, though, and that resulted in an unprecedented combination of weight and horsepower in the rubber-tracked tractor.
“Customers said, ‘We’re limited with steel-track machines, because of speed,’” Bayless says. “Top speed of a steel-tracked machine is 6, maybe 7, miles per hour. Top speed on this machine [the 764HSD] is 16.”
And that speed is not reserved for transport. The machine is intended to fine grade efficiently with its 11-foot blade (same part number as that on the 115-horsepower 700J dozer) at more than double the speed of conventional steel-track dozers.
“In order to move the same [load of] material faster, you have to have a lot more horsepower,” says Bayless. “We need that extra horsepower to increase production.”
Ackert confirms that the dozer works fast.
“As far as cleanup, if you had a D6 working all day, you could come back in behind it and knock down windrows in an hour and a half,” he says.
“If the grade was within a tenth and you clicked on the GPS . . . get outta the way. Here I come,” Ackert exclaims. “It’s unbelievably fast. It’s amazing how much the suspension system will soak up in terms of unevenness—and the machine still maintains the grade.”
“For working a flat pad, Topcon’s 3D MC2 system has allowed us to grade at speeds up to 10 or 11 mph within GPS tolerance,” says Bayless. “Once you get into complex 3D designs, it’s going to slow down a little bit. But for a flat pad, spreading loose fill rock, those speeds are definitely attainable with this machine. It’s been confirmed on our demo sites; it’s been confirmed on customer jobsites all over the country.”
Despite moving some big windrows of material, it’s clear that the 764HSD is primarily a grading machine. Proximity of the cab windscreen to the blade, for example, discourages use of the machine for land clearing or demolition. But we wanted to get a feel for the limits of how well the tractor transfers torque into the terrain. Ackert suggested we hook it up to a 16-foot box blade that Local 150 normally uses behind a big quad-track ag tractor with nearly twice the horsepower.
“I was really surprised to fill that box blade up to the top and see that it [the 764HSD] would still pull it,” he says. “I did that purposely; I put the blade into the ground to see what it would do. She would squat, but she would still pull it.”
In all the work he did that day, Ackert says he didn’t notice much track slip. Certainly no more than he would expect from a conventional steel-track dozer.
“It hardly ever slipped,” Ackert says. “Working in sandy material, this would be light years ahead of steel as far as undercarriage wear.”
The unique configuration of the machine gave the veteran dozer man a different perspective on the work.
“You sit up over the top, so the visibility is outstanding,” Ackert says. “When you sit in a dozer, you sit on the back end. When you’re grading, you’re used to feeling everything. Now [in the 764’s cab], it’s right up here.
“It takes you a little while to get used to; you don’t have the same feel that you used to on the steel-track dozer,” he adds. “In a dozer, as soon as you turn, you know the tractor’s turning.”
He says the “feel” adjustment comes in the delay between moving a lever to steer and when the turning rear frame actually starts swinging the blade in the desired direction.
“This is more like a compactor, because you’re sitting on the front frame, right on top of everything,” Ackert concludes. “It’s a different feel.”