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b Gravity feed lubrication systen The gravity feed lubrication system is primarily used in transfer cases and nosebox assemblies This system

usually has a pump to transfer the oil from the reservoir to an area above the

components to be lubricated Nature takes over at that point through

gravity which distributes the oil (fig 3-7) Rotating components also pick up oil and splash it throughout the assembly lubricated Fig 3-8 Dip feed system Fig 3-7 Gravity feed system

c Dip feed system The dip feed system is used in most axle and

differential assemblies In the dip feed lubrication system (fig 3-8), the components are partially submerged in oil As the parts rotate, the oil is carried directly to the surfaces to be

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a Splash feed system The splash feed lubrication system was once used extensively in automotive engines The connecting rods in engines using this lubrication system are equipped with dippers on their ends As the rods rotate through the crankcase, the dippers pick up oil and splash it upward, lubricating the rest of the components (fig 3-9) This system works much like the dip feed system The splash feed system is still used in combination with other systems on large engines and is also used on smaller engines as the main source of

lubrication

Let's have some more fun Unscramble the words to find the components that use the listed lubrication systems If you know the answers, this should be easy t 1 4 4 4 ⁄ ⁄ ⁄ ⁄ ⁄ ⁄ 4 ⁄ ⁄ 777 777772///////272

Fig 3-9 Splash feed

° Full force feed system -_ticmaotua misanstrnois e Splash feed system - lsilma neengsi

e Gravity feed system - anerfsrt sesac e Dip feed system - enfdifalitre

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3104 Components of the Engine Lubrication System

To properly service, troubleshoot, or repair the components of a lubrication system, you must know the components that make up the system and understand how they operate Remember, your engine's life depends on the lubrication system Let's begin at the

bottom of the engine and work our way up

a Oil pan and sump The oil pan 1S normally made of thin sheet

metal or cast aluminum It bolts to the bottom of the engine block and holds the oil for the

lubrication system (fig 3-10) Most engines have a magnetic drain plug located in the sump (lowest point) of the pan Using this kind of plug helps reduce wear by

removing any metal shavings from

the oil Baffles keep the oil Fig 3-10 Oil pan and sump from splashing around in the pan

-b Oil] pumps The oil pump is the heart of the lubrication system It pulls the oil from the sump and delivers it under pressure through the engine oil filter and galleries to the engine components and

bearings

There are several types of oil pumps but the two most commonly used are the gear type and rotor

type (fig 3-11)

Fig 3-11 Rotor and gear Oil pumps

The unscrambled words from the previous page are:

° Full force feed system -_automatic transmission

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The rotor oil pump (fig 3-12) has a set of star shaped

rotors inside its housing; they work together to

pressurize the oil As the oil pump drive shaft turns, the inner rotor, which is attached to the shaft, causes the outer rotor to spin The eccentric action of the two rotors forms pockets that

change in size

A large pocket is formed on the inlet side of the pump

As the rotor turns, the oil-

filled pocket becomes smaller

as it nears the outlet Fig 3-12 Rotor oil pump This squeezes the oil, forcing operation

it out of the pump and into the oil galleries

The spinning action is repeated over and over to produce a relatively smooth flow of oil

The gear type oil pump PUMP HOUSING

(fig 3-13) has a set of gears Z2

that produce 1ubrication IDLER GEAR FES LS VE p> INTERNAL SEAL FORMED system pressure

Oil on the inlet side of the pump is caught between the gear teeth and carried around the inside wall of the pump

housing The rotation and LOW OUTLET

meshing of the gear teeth

create a seal to pressurize IN GEAR

the oil and force it through TEETH

the pump outlet and into the INTERNAL

oil galleries | DRIVE GEAR SEAL FORMED

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Most oil pumps are mounted on the engine so that they can be gear driven from the crankshaft or camshaft They may also be mounted externally or internally An example of an external pump is

shown in figure 3-14 This pump is used in the M939 series vehicle engines and is driven directly off the engine camshaft The drive gear turns the oil pump shaft which powers the internal pump drive and idler gears An example of an internal pump is shown in figure 3-15; this is the dual gear type pump used in the LVS engine FUME DRIVE DRIVE GEAR ® 0 2nd DRIVE AND IDLER

IDLER GEAR SHAFT

GEAR SHAFT SHAFT

Fig 3-14 Gear type oil pump OIL PICKUP OIL PUMP y SCREENS DRIVE = GEAR OIL PICK UP TUBE CRANKSHAFT h1 1g N09 ĐIẾt 0 [Ƒ

đ ) _ : / 0 ` “Ni! OIL PUMP ENGINE BLOCK

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c Oil pickup tube and screen

line for the pump One end of the pickup is attached to the oil The oil pickup is the supply pump inlet while the other end extends into the oil sump

most cases, the pickup is attached to an oil screen shows a good example of this arrangement

In

Figure 3-15 The pickup screen

prevents large dirt particles and other contaminants from entering the pickup tube and oil pump

ad Oil pressure relief valve Often called an oil pressure regulator valve, the oil

pressure relief valve (fig 3- 16) is a spring-loaded valve located in the oil pump, engine block, or oil filter housing This valve's job is to regulate oil pressure Why is it CLOSED -—®r~ oP parE te etal RELIEF VALVE NORMAL OIL RELIEF VALVE N - Ki TS EXCESS OIL

needed? Oil pumps are designed PRESSURE PRESSURE to pump a large amount of oil,

but when enough oil has been

pumped and the usable pressure Fig 3-16 Oil pressure relief

limits are reached, the

pressure relief valve opens to allow excess oil to return to the sump

e Oil galleries

valve

Oil galleries are small passages cast or machined into the cylinder block and head (fig 3-17)

oil to flow to the engine bearings and other moving parts

They allow Main oil galleries are the large passages through the center of the block They provide an oil passageway to the crankshaft

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SPLASH LUBRICATION OIL PAN SPLASH LUBRICATION PICK-UP SCREEN OIL FILTER | OIL PUMP BYPASS VALVE

Fig 3-17 Oil galleries

f Oil filter The oil filter removes small particles of metal, carbon, rust, dirt, and other contaminants from the motor oil By doing this it protects moving engine parts from abrasive wear The oil filter often has a filtering element made of paper or cotton; as the oil flows through the filter, the element traps contaminants

An 01il filter by-pass valve is commonly used to protect the engine from oil starvation should the filter element become

Clogged The valve opens if excessive pressure is formed in the filter and allows unfiltered oil to flow to the engine

components, thus preventing major damage (fig 3-18) We don't really want unfiltered oil lubricating engine parts, but

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There are two basic types of oil filters: the spin-on type and the cartridge type

e The spin-on filter (fig 3-18) is self contained This means that the filter shell, element, and bypass valve are all contained in one neat little package This filter is used one time and thrown away Spin-on type filters are used on equipment such as the HMMWV, CUCV,

and LVS |

e The cartridge type filter (fig 3-19) has a separate element and housing To service this type filter, you remove the reusable housing, install a new element, and replace the housing The M800 and M939 series vehicles have this type filter SEAL HOUSING BY PASS VALVE ELEMENT Fig 3-18 Spin-on type oil Fig 3-19 Cartridge type oil filter filter

g Oil sending unit and gauge An alert operator (you!) can prevent an engine from being destroyed by lubrication system failure The oil pressure gauge is designed to give you the information you need and it gets that information from a sending unit located in an oil gallery The gauge and sending unit work together to provide an accurate reading of the oil pressure The sending unit is a pressure sensitive variable resistance unit What does that mean and how does it work? Well, after we look at the operation, you'll be able to answer these questions

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The oil applies pressure to a diaphragm within the sending unit (fig 3-20) As the oil pressure increases, the sending unit Giaphragm deflects in proportion, causing a corresponding change in the sending unit's resistance LEFT COq, RIGHT COIL

IGNITION SLIDING @” ————— c h TERMINAL

SWITCH WIRE 2 CONTACT Or on

( bs A zô LEVER —2——> : ` «—— SENDING PRESSURE UNIT GROUND | BATTERY SPRING OIL PRESSURE AND + OIL PRESSURE

Fig 3-20 Oil pressure gauge and sending unit circuit

Low oil pressure deceases the sending unit's resistance, which in turn causes higher current flow from the battery through the left coil of the gauge, through wire 1, and on to the sending unit This current flow causes the magnetic field of the left coil of the gauge to be stronger than the magnetic field of the right coil, pulling the pointer to the left and giving a low oil pressure gauge reading

High engine oil pressure increases the resistance in the sending unit which causes the current to flow from the battery, through the left gauge coil, and then through the right gauge coil to ground The resistance of the right coil is less than that of the sending unit, so the current, taking the path of least

resistance, deflects the pressure gauge needle to the right The gauge then indicates a high oil pressure reading

h Oil coolers Since we covered oil coolers in the previous study unit, they will not be covered in depth here You should remember that an oil cooler works somewhat like a radiator and uses the engine coolant or air flow to remove excess heat from the oil Doesn't this sound familiar? I sure hope so

Okay, you have just covered the engine lubricating system Let's see if you can list the components that make up that system To make this more interesting, try to do it without going back

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The correct answers are:

) Oil sump and pan ) O11 pump

) O11 pickup tube and screen ) Oil pressure relief valve )ạ O1l galleries ) Oil filter ) O11 sending unit and gauge ) Oil cooler (1 (2 (3 (4 (5 (6 (7 (8

Now for your score: Eight out of eight classifies you as a

"pro," seven out of eight will give you the title "semi-pro," but Six out of eight or less means that you should go back and study the engine lubrication system more thoroughly!

3105 Automatic Transmission Lubrication System

Since the automatic transmission lubrication system works Similarly to the engine lubrication system, we won't go into

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The lubrication pump in the automatic transmission not only provides lubrication for all the moving parts but also provides the operating pressure for the valves, servos, and pistons that are used to control the transmission

The pump illustrated in figure 3-21 is a rotor type pump which is driven by the transmission's torque converter An oil pressure regulator limits the oil pressure to the amount the transmission needs for proper operation The oil filter on most automatic transmissions is located in the oil pan Some models use a

pickup tube while others have eliminated the tube by mounting the filter directly to the bottom of the valve body assembly The transmission on the LVS also uses a spin-on filter as a secondary filter

Most large truck automatic transmissions have transmission oil temperature gauges to warn operators of transmission overheating These large transmissions also use oil coolers to keep the oil temperature in the normal operating range

The lubricating oil used in automatic transmissions varies from one transmission to another So, before servicing a

transmission, you should refer to the vehicle lubrication order It specifies the correct lubricant to use Lubrication orders will be covered later in this study unit

Answer the following question to see how well you're doing What component in the automatic transmission provides operating

pressure for servos, valves, and pistons? If you said the oil

pump, you're absolutely correct |

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3106 Manual Transmission Lubrication System

The manual transmission uses a combination of the splash and dip feed methods of lubrication It doesn't have an oil pan or sump; the housing contains the lubricant The oil is filled to and maintained at a level (fig 3-22) that ensures the adequate

lubrication of all moving parts

The lubricant is also the primary source of cooling for the manual transmission As the lubricant splashes over the gears and bearings, it picks up heat Once again, the oil volume must be properly maintained to ensure adequate cooling

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3107 Transfer Case Lubrication System

Most large transfer cases, such as those used in the LVS and the M939 series vehicles (figures 3-23 and 3-24), use a pump to

transfer the oil from the bottom of the transfer case to the top Nature then takes over to allow the force of gravity to deliver the lubricant to all moving parts LUBRICATION PUMP ) LUBRICATION

Fig 3-23 LVS transfer case Fig 3-24 M939 series lubrication pump transfer case lubrication

pump

Now think back Do you remember which type of lubrication system this is?

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Lubrication oil is the primary means of cooling for most transfer cases The HMMWV transfer, however, is cooled a little

differently It has an internal oil cooler which uses

transmission oil to help remove the heat from the transfer case (fig 3-25) TRANSFER CASE OIL COOLER ENGINE OIL COOLER TRANSMISSION OIL COOLER TRANSFER 4 CASE T v s

Fig 3-25 HMMWV transfer case internal cooler

As shown in figure 3-25, transmission oil leaves the

transmission, flows through the transmission oil cooler, the transfer case internal oil cooler, and then returns to the transmission There is no direct contact between the transfer case oil and the transmission oil

So, you could say that the transmission oil cooler assists in

cooling the

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Now, could a loss of transmission oil, without obvious external leaks, be an indicator of a damaged transfer case oil cooler? You bet it could How would you know? Well, there's a very easy way that you could see if this has happened: check both the

transmission and transfer oil levels the transmission oil level would be low and the transfer case would be overfull

3108 Axle and Differential Lubrication System

Axles and differentials are normally lubricated by the dip feed method The axle assembly housing is the reservoir for the

lubricant Some large vehicles, such as the LVS, have axle

assemblies that use an inter-axle differential These axles have a lubrication pump to transfer lubricant from the bottom of the axle housing to the top of the inter-axle differential Gravity then delivers the oil to all moving parts

The LVS also has a nose box assembly to transfer power Mounted on the number one axle, it has its own lubrication system which is separated from the axle assembly by two seals on an input

shaft The nose box center gear drives an oil pump, but the pump supplies lubricant for the differential, not the nose box itself There is no outside means of cooling for axle assembles Since

internal lubricants perform this function, a heavy gear oil is used Most axle housings also use magnetic drain plugs to attract and hold any metal particles

As with other components, always refer to the lubrication order before servicing or checking axle assemblies Keep a close eye on small components such as the axle shift units Since they hold very little lubricant, any sign of wetness indicates a possible problen

Lesson Summary In this lesson you identified the functions of lubricants and types of lubrication systems You determined the types of oil and grease to use in different climatic conditions, and described the operation of lubrication system components As stated earlier, oil is the life blood of any mechanical systen Just as your body will cease to function without blood,

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Exercise: Complete items 1 through 16 by performing the action required Check your responses against those listed at the end of this study unit

What are the four functions of lubricants? d Would you use a low or a high viscosity oil during summer Climatic conditions?

Would you use a 10 weight or a 50 weight oil during winter climatic conditions?

What type of oil is used during both winter and summer Climatic conditions?

There are two basic greases used for motor

transport equipment; they are GAA and GGP The temperature range of limits its use to temperatures above 0°F The chemical makeup of these two lubricants prevent them from being used

Matching: For items 6 through 10, match each component in column 1 to its primary lubrication system listed in column 2 Place your responses in the spaces provided Selections listed in column 2 may be used more than once

Column 1 Column 2

Component Lubrication System

6 Engine a Dip feed

7 Automatic transmission b Full force feed 8 Manual transmission c Gravity feed 9 Transfer case dad Pump feed

10 Axles e Splash/dip feed

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Matching: For items 11 through 16, match each component listed in column 1 to its function in column 2 Place your responses in the spaces provided Column 1 Component 11 12 13 14 15 16 Oil pump | Oil pressure relief valve Oil filter Oil sending unit and gauge Transmission oil pump “ HMMWV transmission 011 cooler Column 2 Function Delivers lubricant under pressure |

Removes large particles Holds oil supply for the lubrication system

Provides operating pressure for valves, servos, and pistons Provides accurate reading of oil pressure Removes small particles from the oil

Limits maximum oil pressure Provides a passage for the oil to travel

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Lesson 2 LUBRICATION ORDER LEARNING OBJECTIVE

1 Given a situation involving vehicle lubrication and a lubrication order, use the lubrication order to determine the required lubricants for selected components

2 Given a lubrication order and a list of terms/symbols, extract the meaning of the terms/symbols from the

lubrication order

3201 Purpose of the Lubrication Order

AS an organizational mechanic, you will normally not be able to specialize on any one vehicle or system You will be required to perform maintenance on all equipment The lubrication (lube) order provides you with a single consolidated source of

instructions Like a map, it lays out everything that you need to know to properly service and lubricate the equipment

The lubrication order (LO) is made of laminated material which will not be damaged if grease or oil is spilled on it

3202 Content of the Lubrication Order

The lubrication order has four parts Let's look at each one a Cover/instructional page The cover page (fig 3-26) begins with the lubrication order number and the date of publication This is followed by the nomenclature (Name/Model/NSN) of the vehicle or series of vehicles that the order covers On most lube orders, you will find descriptions of terms, symbols, and codes that are used throughout the order As a good example, look at the cover page in figure 3-26 Notice that the first three paragraphs provide information on service intervals All of this information is very important and most of it will be covered more thoroughly in this lesson There are terms

mentioned in the first paragraph that you may not be familiar with Let's define then:

© Hard time is the established time interval at which the particular service is to be performed

© On-condition means that the service is performed as required to maintain the equipment in an operational condition

© The Army Oil Analysis Program (AOAP) is a program

established to extend the service life of equipment by performing spectrometric analysis of used oil In other words, the oil is tested to determine if it needs to be changed and to identify contaminants This program will be covered in another lesson

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