JD 748G-11 Gears Up

The John Deere 748G-11 skidder, part of Deere's new line of G-11-series skidders, is getting good marks from logging contractors for its new transmission.

By Paul MacDonald
Copyright 1998. Contact publisher for permission to use.

The 748G-11 grapple skidders from John Deere may be relatively new to the market, but the machines are already proving themselves in bush operations in several parts of the country, including Ontario and British Columbia.

John Deere JD 748G-11

John Deere JD 748G-11 Grapple Skidder

The G-11 series consists of five new skidder models - three grapple skidders and two cable skidders. The new lineup retains the direct-drive powertrain, higher-horsepower engines and the stable platform that have made the G-series a success in the market, says Deere.

One of the first contractors to work with the new 748G-11 was Herman Viel, who operates in northwestern Ontario. His family is well established in the area. Herman's father Guy started a contract logging operation in the region in the 1970s. Herman started working with his father and then branched out on his own several years ago, doing contract skidding.

This past summer, Hen-nan Viel ran the 748G-11 in an operation located 100 km north of Thunder Bay, near Armstrong, and was contracting to Mark Mrakic of Ground Zero Chipping. Mrakic operates with a Peterson Pacific DDC 5000 chipper and was contracting for Avenor with this cut, as well as hauling chips to Thunder Bay. In this operation, Viel was skidding in wood that had been damaged in a fire in 1997.

The machine gets good marks for power from Herman Viel and his operators. "We're very happy with the kind of power and torque that we get from the machine," says Viel. The 748G-11 is at the top of the improved line in terms of power, which is supplied by a John Deere 6076T diesel engine with maximum torque rise of 35 per cent at 1,350 rpm. This gives an operator 532 ft.-lbs. of pulling power on a wheelbase of more than 12'on the machine.

The 748G-11 came with a package that Ontrac Equipment Services (formerly Wood-Land Tractor), the Deere dealer for Ontario, says is essential to operating in northwestern Ontario. The package includes T1 steel underbelly pans to protect against rocky conditions, and differential guards. "Without that, contractors would be looking at damage within the first week given the rocky conditions they are working in," says Tom Trembath, sales representative of Ontrac Equipment. "It's a very necessary package and in the best interest of the contractor because it helps to keep the machines up and running."

"Contractors here aren't that different from anywhere else," explains Trembath. "Logging equipment is expensive these days and they want to keep it operating as much as they can, with as much of the maintenance taken care of for them as possible. We're talking about operating in some rugged conditions in this part of Ontario." Maintenance is certainly a consideration, but generally the less the contractor has to do, the better, he says. "They want to be able to run the heck out of their machines in terms of hauling wood.

"The key is focusing on your uptime, not your downtime. Contractors can't afford to have equipment down, which is also where having a good parts and service base plays into the equation." To draw a comparison, says Trembath, equipment time is a perishable quantity. Once production time is lost on a machine, it can't be made up again - revenue that could have been realized if the machine had been operating is lost.

Vernon, BC contractor Keith Balcaen knows all about uptime - his 10 skidders were able to achieve an uptime rate of 98 per cent last year, he says. "I fink we've got one of the best preventative maintenance pro grams in BC."

Balcaen harvests 350,000 cubic metres a year, with operations in the Okanagan for Riverside Forest Products, and further north in BC's Central Interior for Northwood Timber. He took delivery of two 748G-11s from BC John Deere dealer Coast Tractor this past summer and is enthusiastic about the machines. "They're probably the best grapple skidder on the market," he says.

Balcaen points out three main improvements of the G-11 over its predecessor - the extra power, the tilt cab and the transmission. "The reverse speeds in the other transmission were too high and you could power it out," he says, also pointing out the improved gear spacing in the forward speeds as a plus. The DF-180 transmission offers more working gears in reverse, with a lower first reverse for better torque when backing up slopes. "The new transmission is also much smoother shifting, which should result in a better life for our powertrains."

The new DF-180 direct-drive powershift transmission, developed by John Deere's Funk Division for all five G-11 skidder models, is a countershaft design, as opposed to the planetary system in the G-series skidders. The new design serves up eight forward and seven reverse speeds, with a microprocessor controlling the shifts, smoothly and consistently. Spacing is even through the first six forward gears to better match engine rpm to the load and make it easier for the operator to always find the fight gear.

The new transmission system also has an inching clutch pedal mechanism that requires significantly less effort to actuate, and has improved modulation. This results in a pedal that is easier to use and offers a smooth action throughout the clutch travel, says Deere. Lubrication and cooling oil systems service the new inching pedal.

With narrower travel speeds in the lower gears, operators can more effectively and smoothly run in second and third gear and improve their travel times, resulting in a few more trips a day between the bush and roadside, says Wood-Land Tractors' Tom Trembath. "Cycle times are of course key to the overall efficiency of the skidding operation."

A new extreme-duty axle has been developed for the 748G-11 and its sibling machine, the 648G-11, and is recommended for severe conditions, such as operating with chains in rocks and snow with a high-capacity grapple. This new optional axle utilizes a heavy-duty planetary carrier assembly designed to last up to four times longer than the standard model. The axle is actually only an option outside of Canada, as the heavy-duty axles will be standard on all 648 and 748 units sold in Canada.

Also new to the G-11 series skidders are oil-lubricated outer axle bearings, eliminating the need for routine greasing. The bearings reduce the potential of axle failure caused by improper maintenance. "Previously, these bearings had to be greased manually every eight hours," says Trembath. "Deere has gone to a system where the bearings are sitting in an oil bath and bathe themselves.

"This is part of making the machines as maintenance-free as possible so the operator does not have to do as much at the end of his shift. For example, operators now just have to grease the arch pins, the boom pins and the centre pins or about a dozen grease points. On the 748G-11, there are four less grease pins, which means 25 per cent less maintenance in that area."

For Herman Viel and other contractors, the less time they and their operators have to spend on maintenance, the more time the machine can be operating and skidding wood. After a 12-hour shift, the operator can do a quick maintenance check of the machine and then hand it over to the second shift operator. "These operators are paid to haul wood and the more cords they haul to roadside, the more they get paid," says Trembath. "It's all about production and keeping the machines working. It's as simple as that."

The 748G-11, like all the machines in the G-11-series, features a cab that tilts to make it easier to access the transmission and to permit easy service of the components located in the machine's mid-section. Using an onboard hand-operated hydraulic pump, the operator can fully tilt the cab in about 15 minutes.

Hydraulics on the 748 G-11 include a new pump with an increased capacity of about 10 per cent. The pump now generates oil flow at 42 gpm for faster response times and overall increased productivity.

A new electronic monitoring cluster provides instant visual display of the condition of 16 vital machine functions. The system also has an audible alert when a function requires immediate attention. The system includes LCD readout of engine speed, gear selection and direction, and also provides transmission diagnostic data in the form of service codes.

Besides the mechanics, the operator's cab is an area where Deere, like all equipment manufacturers, continues to do some tweaking to make further improvements. In areas like northwestern Ontario and the BC Interior, where operators are looking at summer temperatures in the high 20s and up-air conditioning not only makes for a more comfortable operating environment, it is also likely to result in an increase in productivity. With skidder operators at the controls 12 hours a day, keeping them relatively comfortable pays off.

"With the kind of summers we have in the BC Interior, it's not even a question of getting air conditioning on our skidders," says contractor Keith Balcaen.








Copyright 1998 Forestnet.