INTRODUCTION
Shown is the right side of a 777D Update truck. The fuel tank is located on the right side of the truck.
The standard 777D Update truck has front caliper disc brakes.
Oil cooled front brakes are available as an option. Both brake types are covered in this presentation.
The major features added to the 777D Update truck are: improved cab, two Electronic Control Modules (Transmission/Chassis and Brake), a pressure compensated steering system and an electronically controlled hoist system.
Some of the specifications of the 777D Update Truck are:
* Serial No. Prefix: AGC (previous 777D: 3PR)
* Empty weight: 80160 kg (176722 lbs.)
* Load carrying capacity: 90.9 metric tons (100 tons)
* Gross Machine Weight (GMW): 161028 kg (355000 lbs.)
* Length: 9.78 m (32.1 ft.)
* Width: 5.53 m (18.2 ft.)
* Height: 5.00 m (16.4 ft.)
* Body Up Height: 9.95 m (32.7 ft.)
* Maximum ground speed at 1900 engine rpm: 63.7 km/h (39.5 mph).
Hydraulic tank group
Shown is the left side of a 777D Update truck. The hydraulic tank group is visible. The hydraulic tank group consists of two separate tanks: the hoist, brake and torque converter hydraulic tank (front) and the transmission hydraulic tank (rear). The transmission hydraulic system is separated from all of the other hydraulic systems.
The service/retarder air tanks, the front brake master cylinder, and the brake oil makeup tank are located on the hydraulic tank group.
Transmission/Chassis Electronic Control System
The second generation Electronic Programmable Transmission Control (EPTC II) has been replaced with the Transmission/Chassis Electronic Control System. The Transmission/Chassis Electronic Control Module (ECM) controls the same functions as the EPTC II plus the hoist and
some other functions.
Brake Electronic Control System
The Automatic Retarder Control (ARC) and the Traction Control System
(TCS) control modules have been replaced with one Brake System ECM.
The Brake System ECM controls both the ARC and the TCS functions.
The TCS is now connected to the CAT Data Link and the Electronic
Technician (ET) service tool can be used to diagnose the TCS.
Folded-core radiator
Shown is the front of a 777D Update truck. The 777D Update truck uses a folded core radiator. The folded core style radiator provides the convenience of repairing or replacing smaller individual cores.
Truck body options
Shown is the rear of a 777D Update truck. Two body options are available for the 777D Update truck:
* A 12 degree flat floor design that provides uniform load dumping, excellent load retention and a low center of gravity.
* A dual-slope design with a "V" bottom main floor to reduce shock loading, center the load and reduce spills.
All internal wear surfaces of the truck bodies are made with 400 Brinell hardness steel. All attachment body liners are also made with 400 Brinell hardness steel. The external components of the bodies are made of steel with a yield strength of 6205 bar (90000 psi).
* Rear suspension cylinders.
The rear suspension cylinders absorb bending and twisting stresses rather than transmitting them to the main frame.
Read the Operation and Maintenance Manual
MAINTENANCE
Before working on or operating the truck, read the Operation and Maintenance Manual thoroughly for information on safety, maintenance and operating techniques.
Safety precautions and Warnings are provided in the manual and on the truck. Be sure to identify and understand all symbols before starting the truck.
The first step to perform when approaching the truck is to make a thorough walk around inspection. Look around and under the truck for loose or missing bolts, trash build-up and for coolant, fuel or oil leaks.
Look for indications of cracks. Pay close attention to high stress areas as
shown in the Operation and Maintenance Manual.
Maintenance 10 hours/daily
The following list identifies the items that must be serviced every 10 Hours or Daily.
- Walk-Around Inspection: Check for loose or missing bolts, leaks,
trash build-up and cracks in frame structures and body support pads
- Tire condition and inflation pressure
- Wheel nuts - Suspension cylinders
- Primary fuel filter - Fuel level and moisture
- Rear axle breather - Hoist, converter and brake oil
- Transmission oil - Air tank moisture
- Brake cylinders and breathers - Radiator
- Fan belts - Ether cylinder
- Steering system oil - Engine crankcase oil
- Batteries - Air filters and precleaners
- Windshield washer fluid level - Cab fresh air filters
- Back-up alarm - Secondary steering
- Seat belts - Brakes.
Front wheel bearing magnetic inspection plug
The front wheel bearing oil level is checked and filled by removing the plug (1) in the center of the wheel bearing cover. The oil should be level with the bottom of the plug hole. The fill plug is a magnetic plug.
Inspect the fill plug weekly for metal particles. If any metal particles are found, remove the wheel cover and inspect the bearings for wear. The oil is drained by removing the drain plug (2).
The service interval for changing the front wheel bearing oil is 500 hours.
Use only Transmission Drive Train Oil (TDTO) with a specification of (TO-4) or newer. TDTO TO-4 provides increased lubrication capability for bearings.
Check the tire inflation pressure. Operating the truck with the wrong tire inflation pressure can cause heat build-up in the tire and accelerate tire wear.
NOTE: Care must be taken to ensure that fluids are contained while performing any inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid in suitable
containers before opening any compartment or disassembling any component containing fluids. Refer to the "Tools and Shop Products Guide" (Form NENG2500) for tools and supplies suitable to collect
and contain fluids in Caterpillar machines. Dispose of fluids according to local regulations and mandates.
Front suspension cylinder charge.
Check the front suspension cylinders for leaks or structural damage.
Check the charge condition of the front suspension cylinders when the truck is empty and on level ground. Measure the charge height of the suspension cylinders and compare the dimension with the dimension that was recorded the last time the cylinders were charged. Recharge the cylinders with oil and nitrogen if necessary.
A grease outlet fitting is located on one side of each front suspension cylinder. The grease supply fitting (arrow) is located on the opposite side of the suspension cylinder. No grease outlet fittings should be located on the same side of the suspension cylinder as the grease fill location. Having an outlet fitting on the same side of the suspension cylinder as the grease fill location will prevent proper lubrication of the cylinder.
Make sure that grease is flowing from the outlet fittings to verify that the suspension cylinders are being lubricated and that the pressure in the cylinders is not excessive.
Brake linings
Inspect the brake linings (1) for wear. The thickness of the brake linings (not including carrier) must not be less than 3.15 mm (.125 in). Measure the lining at both ends because one end can wear more than the other.
The clearance between the brake carrier guide pins (2) and the brake disc (3) must not be less than 1.5 ± 0.5 mm (.06 ± .02 in.).
Primary fuel filter
The primary fuel filter (screen) (1) is mounted behind the front engine mount on the right side of the engine. Inspect the condition of the screen at regular intervals. A plugged screen may cause low power or prevent the engine from starting.
An engine oil level switch (2) provides input signals to the Engine ECM.
The Engine ECM provides an input signal to the Caterpillar Monitoring System, which warns the operator when the engine oil level is low and it is unsafe to operate the truck. Operating the truck with low engine oil may cause damage to the engine. The ENGINE OIL LEVEL LOW message is a Category 2 or 3 Warning.
Jacket water coolant S•O•S tap
Jacket water coolant samples can be taken at the Scheduled Oil Sampling (S•O•S) coolant analysis tap (arrow). The tap is located behind the jacket water pump on the right front of the engine.
Transmission charging filter
Located behind the right front tire is the transmission charging filter (1). Transmission oil samples can be taken at the Scheduled Oil Sampling (S.O.S) tap (2).
An oil filter bypass switch (3) is located on the filter. The oil filter bypass switch provides input signals to the Caterpillar Monitoring System, which informs the operator if the filter is restricted.
Fuel tank
The fuel tank is located on the right side of the truck. The fuel level sight gauge (1) is used to check the fuel level during the walk around inspection. A fuel level sender is located on the fuel level sight gauge.
The fuel level sender provides input signals to the Caterpillar Monitoring System, which informs the operator of the fuel level.
Open the drain valve (2) to remove condensation from the fuel tank.
Inspect the condition of the fuel tank breather (3) and the fuel cap vent (4) at regular intervals.
Fuel can be added at the attachment quick service fuel fill connector (5).
The percentage of sulfur in the fuel will affect the engine oil recommendations. The following is a summary of fuel sulfur and oil recommendations:
1. Use API CH-4 performance oils.
2. With fuel sulfur below 0.5%, any API CH-4 oils will have a
sufficient Total Base Number (TBN) for acid neutralization.
3. For fuel sulfur values above 0.5%, the new oil TBN should be a
minimum of 10 times the fuel sulfur.
4. When 10 times the fuel sulfur exceeds the oil TBN, reduce the oil
change interval to about 1/2 the normal change interval.
Rear brake cylinder
Shown is the rear brake cylinder. The rear brake cylinder is located at the right inner frame to the right of the transmission group. The front brake cylinder is located behind the hydraulic tank group.
Inspect the condition of the breathers (1) for the brake cylinders. Oil should not leak from the breather. Oil leaking from the breather indicates that the oil piston seals in the brake cylinder needs replacement. Air flow from the breather during a brake application indicates that the brake cylinder air piston seal needs replacement.
If air is in the system or a loss of oil downstream from the cylinders occurs, the piston in the cylinder will overstroke and cause an indicator rod to extend and open the brake overstroke switch (2). The switch provides an input signal to the Caterpillar Monitoring System, which informs the operator of the condition of the service/retarder brake oil circuit. If an overstroke condition occurs, the problem must be repaired and the indicator rod pushed in to cancel the warning.
NOTE: The front brake cylinder does not have an overstroke switch.
Final drives
The rear axles are equipped with planetary-type final drives. Rotate the final drive until the cover and plug are positioned as shown. The final drive oil level is checked and filled by removing the magnetic plug (1).
The oil should be level with the bottom of the plug hole. Fill the rear axle housing with oil before filling the final drives with oil. Allow enough time for the oil to settle in all of the compartments. This can be as much as 20 minutes during cold temperatures. The oil is drained by removing the drain plug (2).
The magnetic inspection plugs should be removed weekly from the final drives and checked for metal particles. For some conditions, checking the magnetic plugs is the only way to identify a problem which may exist.
Use only Transmission Drive Train Oil (TDTO) with a specification of TO-4 or newer. TDTO TO-4 oil provides:
* Maximum frictional capability required for gears.
* Increased lubrication capability for bearings.
* Flush all axle components after a failure
NOTICE
The rear axle is a common sump for the differential and both final drives. If a final drive or the differential fails, the other final drive components must also be checked for contamination and then flushed. Failure to completely flush the rear axle after a failure can cause a repeat failure within a short time.
Differential magnetic inspection plug
Check the differential oil level by removing the magnetic inspection plug (1). The oil should be level with the bottom of the fill plug opening.
Inspect the rear suspension cylinders for leaks or structural damage. Check the charge condition of the rear suspension cylinders when the truck is empty and on level ground. Measure the charge height of the suspension cylinders, and compare the dimension with the dimension that was recorded the last time the cylinders were charged. Recharge the cylinders if necessary.
Inspect the condition of the rear axle breather (2) at regular intervals. The breather prevents pressure from building up in the axle housing. Excessive pressure in the axle housing can cause brake cooling oil to leak through the Duo-Cone seals in the wheel brake assemblies.
Body up retaining pins (arrow)
The body up retaining pins (arrow) are stored below the rear of the body.
When work is to be performed while the body is raised, the body up retaining pins must be installed through the pin holes in the body and the rear frame to hold the body in the raised position.
WARNING
The space between the body and the frame becomes a zero clearance area when the body is lowered. Failure to install the body up pins can result in injury or death to personnel working in this area.
Transmission hydraulic tank
The oil level of both hydraulic tanks should first be checked with cold oil and the engine stopped. The level should again be checked with warm oil and the engine running.
The lower sight gauge (3) on the hoist, converter and brake hydraulic tank can be used to fill the tank when the hoist cylinders are in the RAISED position. When the hoist cylinders are lowered, the hydraulic oil level will increase. After the hoist cylinders are lowered, check the hydraulic tank oil level with the upper sight gauge.
Inspect the hoist, converter and brake hydraulic tank breather (4) and the transmission hydraulic tank breather (5) for plugging.
Inspect the condition of both hydraulic tank fill cap vents at regular intervals.
The service/retarder brake air tanks are located on top of the hydraulic tank. Drain the moisture from the tanks daily with the drain valve (6).
When filling the hydraulic tanks after an oil change, fill the tanks with oil to the FULL COLD mark on the sight gauge. Turn on the engine manual shutdown switch (see Slide No. 23) so the engine will not start. Crank the engine for approximately 15 seconds. The oil level will decrease as oil fills the hydraulic systems. Add more oil to the tanks to raise the oil level to the FULL COLD mark.
Crank the engine for an additional 15 seconds.
Repeat this step as required until the oil level stabilizes at the FULL COLD mark.
Turn off the engine manual shutdown switch and start the engine. Warm the hydraulic oil. Add more oil to the tank as required to raise the oil level to the FULL WARM mark.
In both tanks, use only Transmission Drive Train Oil (TDTO) with a specification of TO-4 or newer. TDTO TO-4 oil:
* Provides maximum frictional capability required for clutch discs used in the transmission, torque converter and brakes.
* Increases rimpull because of reduced slippage.
* Increases brake holding capability by reducing brake slippage.
* Controls brake chatter.
* Provides maximum frictional capability required for gears.WARNI
Parking brake release filter
Located in front of the hydraulic tanks are the parking brake release filter (1) and the torque converter charging filter (2). Hoist, converter and brake oil samples can be taken at the Scheduled Oil Sampling (S.O.S) tap (3).
The air dryer (4) is located behind the left front tire. Inspect for oil spray around the air dryer. Oil spray can indicate that a problem exists in the air compressor.N
Engine oil filters
The engine oil filters are located on the left side of the engine. The engine lubrication system is equipped with two oil pressure sensors (1). A sensor is located on each end of the oil filter base. One sensor measures engine oil pressure before the filters. The other sensor measures oil pressure after the filters (sensor shown). The sensors
provide input signals to the Engine ECM. The ECM provides input signals to the Caterpillar Monitoring System, which informs the operator of the engine oil pressure. Together, these sensors inform the operator if the engine oil filters are restricted.
The oil filter base also has a fitting (2) that can be used to drain the engine oil that is trapped above the filters. Do not add oil through the fitting because unfiltered oil will enter the engine. Any contamination could cause damage to the engine.
Aftercooler coolant samples can be taken at the Scheduled Oil Sampling (S•O•S) coolant analysis tap (3). The tap is located behind the aftercooler water pump on the left front of the engine.
NOTICE
When changing the engine oil filters, drain the engine oil that is trapped above the oil filters through the fitting (2) to prevent spilling the oil. Oil added to the engine through the fitting will go directly to the main oil galleries without going through the engine oil filters.
Adding oil to the engine through the fitting may introduce contaminants into the system and cause damage to the engine.
Engine oil S.O.S tap
Engine oil samples can be taken at the Scheduled Oil Sampling (S•O•S) tap (1) located on front of the oil filter base.
Also shown is the engine oil pressure sensor (2) that measures the engine oil pressure before the filters.
Secondary fuel filters
The secondary fuel filters and the fuel priming pump (1) are located above the engine oil filters on the left side of the engine. The fuel priming pump is used to fill the filters after they are changed.
A fuel filter bypass switch (2) is located on the filter base. The bypass
switch provides an input signal to the Engine ECM. The Engine ECM sends the signal to the Caterpillar Monitoring System, which informs the operator if the filters are restricted.
NOTE: If the fuel system requires priming, it may be necessary to block the fuel return line during priming to force the fuel into the injectors.
Manual engine shutdown switch (arrow)
Before climbing the truck ladder, make sure that the manual engine shutdown switch (arrow) is OFF. The engine will not start if the manual shutdown switch is ON. If necessary, the switch can be used to stop the engine from the ground level.
Battery disconnect switch (arrow)
While climbing the ladder, make a thorough inspection of the radiator. Be sure that no debris or dirt is trapped in the radiator cores.
The battery disconnect switch (arrow) is located under a cover on the front bumper near the right access ladder. If the machine is being parked for an extended period (overnight, etc.) turn off the disconnect switch and remove the key.
Batteries
The batteries are located on the right platform. Inspect the battery connections for corrosion or damage. Keep the battery terminals clean and coated with petroleum jelly.
Inspect the electrolyte level in each battery cell, except maintenance free.
Maintain the level to the bottom of the fill openings with distilled water.
WARNING
Batteries give off flammable fumes that can explode resulting in personal injury.
Prevent sparks near batteries. They could cause vapors to explode.
Do not allow jump cable ends to contact each other or the machine.
Do not smoke when checking battery electrolyte levels. Electrolyte is an acid and can cause personal injury if it contacts skin or eyes.
Always wear eye protection when starting a machine with jumper
cables.
Always connect the battery positive (+) to battery positive (+) and the
battery negative (-) to stalled machine frame (-).
Engine cooling systems:
The cooling system on the 777D Update trucks is divided into two systems. The two systems are the jacket water cooling system (right side) and the aftercooler cooling system (left side). These two systems are not connected. When servicing the cooling systems, be sure to drain and fill both systems separately.
The two coolant levels are checked with the jacket water coolant sight gauge (1) and the aftercooler coolant sight gauge (2). Coolant is added by removing the respective radiator cap.
The jacket water and the aftercooler cooling systems each have their own
relief valve (3). If a cooling system overheats or if coolant is leaking from a relief valve, clean or replace the relief valve.
The water used in the cooling system is critical for good cooling system performance. Use distilled or deionized water whenever possible to prevent acids or scale deposits in the cooling system. Acids and scale deposits result from contaminants that are found in most common water sources.
Never use water alone. All water is corrosive at engine operating temperatures without coolant additives. Also, water alone has none of the lubrication properties which are required for water pump seals.
The trucks are filled at the factory with Extended Life Coolant (ELC). If ELC is maintained in the radiator, it is not necessary to use a supplemental coolant additive. If more than 10% of conventional coolant is mixed with the ELC, a supplemental coolant additive is required.
* With conventional coolant, maintain a 3 - 6% concentration of supplemental coolant additive.
* Too much additive will form insoluble salts that cause water pump seal wear, plugging and will coat parts with excessive deposits that prevent heat transfer.
* Not enough additive will result in severe cavitation erosion which will pit and corrode cylinder liner and block surfaces.
* Use the 4C9301 Test Kit to measure the concentration of the supplemental coolant additive in the cooling system.
* Maintain a 30 - 60% concentration of Caterpillar Antifreeze.
* More than 60% antifreeze concentration will reduce freeze protection and cause radiator plugging.
* Less than 30% antifreeze concentration will result in cavitation erosion which will pit and corrode cylinder liner and block surfaces and decrease water pump life.
* Most commercial antifreezes are formulated with high silicate content for gasoline engines and are not recommended for diesel engines.
* The engine should operate between 88 and 99°C (190 and 210°F).
* Operating below this temperature range will cause overcooling problems.
* Operating above this temperature range will cause overheating problems.
* Cooling system pressure should be between 55 and 110 kPa (8 and 16 psi).
* Raising the pressure raises the boiling point. If the pressure is inadequate, the coolant will boil over and the engine will overheat.
* Do not fill the cooling system faster than 20 l/min. (5 gpm).
* Filling the cooling system faster than 20 l/min. (5 gpm) will cause air pockets that could produce damaging steam.
* Keep fan belts adjusted.
* Keep radiator cooling fins straight and clean.
If the truck is equipped with an ether start system, the ether cylinder (4) (not shown) is located in the engine compartment behind the radiator.
Make sure the ether cylinders are not empty. A laptop computer with the Electronic Technician (ET) software installed can be connected to the machine to turn the ether injection system ON or OFF.
The Engine ECM will automatically inject ether from the ether cylinder during cranking. The duration of automatic ether injection depends on the jacket water coolant temperature. The duration will vary from 10 to 130 seconds.
The operator can also inject ether manually with the ether switch in the cab on the center console (see Slide No. 46). The manual ether injection duration is 5 seconds.
Ether will be injected only if the engine coolant temperature is below 10°C (50°F) and engine speed is below 1900 rpm.
Ether starting tip:
* Cold weather causes rough combustion and white exhaust smoke from unburned fuel. Ether injection will reduce the duration and severity of unburned fuel symptoms.
Steering system tank
The steering system tank is located on the right platform
Check the steering system oil level at the sight gauge (1).
The steering system oil filter (2) is located on the side of the steering tank.
The steering system uses a pressure compensated piston type pump. Case
drain oil from the steering pump returns to the steering tank through a case drain filter (3) on the side of the steering tank.
Before removing the cap to add oil to the steering system, depress the pressure release button (4) on the breather to release any remaining pressure from the tank.
Steering system oil samples can be taken from the Scheduled Oil.
Sampling (S.O.S) tap (5) located in the case drain return hose.
The steering system filter base and the case drain filter base have bypass valves that allow the steering oil to bypass the filters if they are plugged.
Engine air intake system components:
Shown are the air intake system components. Check the air filter restriction indicators (1). If the yellow pistons are in the red zone (indicating that the filters are plugged), the air filters must be serviced.
An air filter restriction indicator is also located on the dash . The alert indicator lights when the filter restriction is approximately 6.2 kPa (25 in. of water).
Located next to the air filter housings are the precleaners. Check the dust valves (2) for plugging. If necessary, disconnect the clamp and open the cover for additional cleaning. Replace the dust valve if the rubber is not flexible.
The dust valve is OPEN when the engine is OFF and closes when the engine is running. The dust valve must be flexible and close when the engine is running or the precleaner will not function properly and the air filters will have a shortened life.
Two filter elements are installed in the filter housings. The large element is the primary element and the small element is the secondary element.
Air intake system tips:
* The primary element can be cleaned a maximum of six times.
* Never clean the secondary element for reuse. Always replace the secondary element.
* Air filter restriction causes black exhaust smoke and low power.
Engine oil level dipstick.
Located below a small cover on the engine hood is the engine oil level dipstick and the engine oil fill tube. Check the engine oil level with the dipstick (1) and add engine oil at the fill tube (2).
Use only Diesel Engine Oil (DEO) with a specification of CF-4 or newer.
DEO oil with a CH-4 specification is available and should be used if possible.
CH-4 engine oil:
* Requires more performance tests than previous oils, such as CE or CF, and has a narrower performance band.
* Can withstand higher temperatures before coking and has better dispersing capability for controlling soot.
* Has better fuel sulfur neutralization capability.
Engine oil fill tube
A small air tank (not visible) is located behind the cab . The air tank behind the cab supplies air to the parking and secondary brakes. Drain the moisture from the tank daily with the drain
valve (1). Check the fluid level of the windshield washer reservoir (2).
NOTE: Check the level of all oil compartments again with the engine running after the oil reaches the normal operating temperature.
Air conditioner filter (arrow)
The air conditioner filter (arrow) is located in a compartment in front of the cab. Clean or replace the filter element when a reduction of circulation in the cab is noticed.
10 hours/daily checks performed in the operator's cab
The remaining 10 Hours or Daily checks are performed in the operator's
compartment:
- Brakes: Check operation
- Indicators and gauges: Test operation
- Seat belt: Inspect
- Back-up alarm: Test operation
- Secondary steering: Test operation
The brakes are checked by engaging one of the brake systems and placing the shift lever in FIRST FORWARD. Accelerate the engine until the truck moves. The truck must not move below 1200 rpm. This procedure should be repeated for each brake lever or pedal.
The cab fresh air filter (arrow) is located behind the cover in the right front corner of the cab. Clean or replace the cab fresh air filter when necessary.
THANK YOU FOR YOUR VISITED
INTRODUCE 777D OFF-HIGHWAY TRUCK
Reviewed by heri
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2:10 AM
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Reviewed by heri
on
2:10 AM
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