1988 GMC SIERRA Service Repair Manual

SAFETY NOTICE

Proper serviceand repair proceduresare vital to the safe, re iable operation of all motorvehicles, as well as the personalsafety of thoseper forming repairs This manual outlines proceduresfor servicingand repairingvehicles using safe, effective methods The procedures contain many NOTES, CAUTIONS and WARNINGS which should befollowed, alongwithstandardprocedures to eliminatethe possibility of personal injuryor improper servicewhich could damagethe vehicleor compromise its safety.

It is important to note that repair procedures and techniquesM toolsand parts for servicingmotorvehicles,as well as the skill and experienceof the individual performing the work vary widely It is not possibles to anticipateall of the conceivable ways or conditions under whichvehicles may beserviced, or to providecautionsasto all possible hazardstti£t mayresult Standardandacceptedsafetyprecautions andequipment should be used when handling toxic or flammable fluids, andsafety gogglesor other protectionshould beusedduring cutting, grinding, chiseling,prying or anyother process that can cause mate/ial removalor projectiles

Some procedures require the use of tools specially designedfor a completely satisfied that neither your personal safety,nor the performance of thevehicle specific purpose Before substituting anothertool or procedure, you must be will be endangered

Although information in this manual is basedon industrysojurces and is completeas possibleat the timeof publication,the possibility exists that somecar manufacturersmade laterchangeswhichcould,inot be includedhere Whilestrivingfor totalaccuracy, the authorsor publishers cannot assume responsibility for any errors, changesor omissions that may occur in the compilationof thisdata

PART NUMBERS

Part numbers listed inthis referenceare notrecommendat ences that can be used with interchange manualsand afterm ons by HaynesNorthAmerica, Inc for any product brand name Theyare refer rket supplier catalogsto locateeachbrandsupplier'sdiscrete partnumber

SPECIAL TOOLS

Specialtools arerecommended by the vehicle manufacturer absolutely necessary,they are referredto in the text by thepart priate part number, fromyour local dealer or regional distributo let Beforesubstituting anytool for the onerecommended,

o performtheir specificjob. Usehas beenkept to a minimum, butwhere lumber of thetool manufacturer Thesetoolscan be purchased,under theappro , or an equivalenttoolcan bepurchasedlocally froma tool supplieror partsout readl the SAFETY NOTICE at the top of this page.

ACKNOWLEDGMENTS been Jwiththe

All rights reserved. No part of this book may be reproduce! ingphotocopying, recording or by any information storage or transmitted in any form or by any means, electronic or mechanical, includ >r retrievalsystem,without permission in writing from the copyright holder.

While every attempt is made to ensure that the information in this manual is correct, no liability can be accepted by the authors or pub lishers for loss, damage or injury caused by any errors in, or omissions from,the information given.

HOW TO USE THIS BOOK 1-2

WHERE TO BEGIN 1-2

AVOIDING TROUBLE 1-2

MAINTENANCE OR REPAIR? 1-2

AVOIDING THE MOST COMMON MISTAKES 1-2

TOOLS AND EQUIPMENT 1-2

SPECIAL TOOLS 1-4

SERVICING YOUR VEHICLE SAFELY 1-4 DO'S 1-4

DONTS 1-5

FASTENERS, MEASUREMENTS AND CONVERSIONS 1-5

BOLTS, NUTS AND OTHER THREADED RETAINERS 1-5 TORQUE 1-6

TORQUE WRENCHES 1-6

TORQUE ANGLE METERS 1-7

STANDARD AND METRIC MEASUREMENTS 1-7 SERIAL NUMBER IDENTIFICATION 1-7 VEHICLE 1-7

ENGINE 1-7

TRANSMISSION 1-8

DRIVE AXLE 1-8

TRANSFER CASE 1-8

SERVICE PARTS IDENTIFICATION LABEL 1-10

ROUTINE MAINTENANCE AND TUNE-UP 1-10 AIR CLEANER1-10

REMOVAL & INSTALLATION 1-13

FUEL FILTER1-13

REMOVAL & INSTALLATION 1-13

PCVVALVE1-15

REMOVAL & INSTALLATION 1-15

CRANKCASE DEPRESSION REGULATORAND FLOW CONTROL VALVE 1-16 SERVICING1-16

EVAPORATIVE CANISTER1-16 SERVICING 1-16

BATTERY 1-16

PRECAUTIONS1-16

GENERAL MAINTENANCE 1-16

BATTERY FLUID 1-17

CABLES1-17

CHARGING 1-18

REPLACEMENT 1-18

BELTS1-18

INSPECTION 1-18

ADJUSTMENT 1-18

REMOVAL & INSTALLATION 1-19 BELT ROUTING1-20 HOSES1-23

INSPECTION 1-23

REMOVAL & INSTALLATION 1-23

CV-BOOTS1-24 INSPECTION1-24

SPARKPLUGS1-25

SPARK PLUG HEAT RANGE 1-25

REMOVAL & INSTALLATION 1-25

INSPECTION & GAPPING1-26

SPARK PLUG WIRES 1-27 TESTING1-27

REMOVAL & INSTALLATION1-27

DISTRIBUTOR CAP AND ROTOR1-27

REMOVAL & INSTALLATION 1-27

INSPECTION 1-28

IGNITION TIMING1-28

GENERAL INFORMATION 1-28

CHECKING & ADJUSTMENT1-29

VALVE LASH1-29

ADJUSTMENT 1-29

IDLE SPEED AND MIXTURE ADJUSTMENTS 1-30

CARBURETED ENGINES1-30

GASOLINE FUEL INJECTED ENGINES 1-30

DIESEL ENGINES 1-31

AIR CONDITIONING SYSTEM1-32

SYSTEM SERVICE S REPAIR 1-32

PREVENTIVE MAINTENANCE 1-32

SYSTEM INSPECTION 1-32

WINDSHIELD WIPERS1-33

ELEMENT (REFILL) CARE& REPLACEMENT 1-33

TIRES AND WHEELS 1-33

TIRE ROTATION 1-33

TIRE DESIGN 1-34

TIRE STORAGE 1-34

INFLATIONS INSPECTION 1-34

FLUIDS AND LUBRICANTS 1-35

FLUID DISPOSAL 1-35

FUEL AND OIL RECOMMENDATIONS 1-35

OIL1-35 FUEL1-36

ENGINE1-37

OIL LEVEL CHECK1-37

OILS FILTER CHANGE 1-37

MANUAL TRANSMISSION 1-38

FLUID RECOMMENDATION 1-38 LEVEL CHECK1-38

DRAINS REFILL 1-39

AUTOMATIC TRANSMISSION 1-39

FLUID RECOMMENDATIONS1-39 LEVEL CHECK 1-39

DRAINS REFILL 1-39

TRANSFER CASE 1-40

FLUID RECOMMENDATIONS1-40 LEVEL CHECK1-40

DRAINS REFILL1-40

FRONT AND REAR DRIVEAXLES1-40

FLUID RECOMMENDATIONS1-40 LEVEL CHECK1-40

DRAINS REFILL1-41

COOLING SYSTEM1-41

FLUID RECOMMENDATIONS1-41 LEVEL CHECK1-42

DRAINING S FLUSHING1-42

BRAKE MASTER CYLINDER 1-42

FLUID RECOMMENDATIONS 1-42 LEVEL CHECK 1-42

CLUTCH MASTER CYLINDER1-43

FLUID RECOMMENDATIONS1-43 LEVEL CHECK1-43

POWER STEERINGPUMP1-43

FLUID RECOMMENDATION1-43 LEVEL CHECK1-43 STEERING GEAR 1-43

FLUID RECOMMENDATIONS1-43 LEVEL CHECK1-44

CHASSIS GREASING 1-44

BODY LUBRICATION AND MAINTENANCE 1-45 LOCK CYLINDERS 1-45 HOOD LATCH S HINGES1-45 DOOR HINGES1-45

BODY DRAIN HOLES1-46

FRONT WHEEL BEARINGS 1-46

TRAILER TOWING 1-46

GENERAL RECOMMENDATIONS 1-46 TRAILER WEIGHT1-46 HITCH (TONGUE)WEIGHT1-46 ENGINE 1-47 TRANSMISSION1-47

HANDLING A TRAILER 1-47

JUMP STARTING A DEAD BATTERY 1-47

JUMP STARTING PRECAUTIONS 1-47

JUMP STARTING PROCEDURE 1-47

SINGLE BATTERYGASOLINE AND DIESEL ENGINE MODELS 1-47

DUAL BATTERYDIESEL MODELS 1-48

JACKING 1-48

JACKING PRECAUTIONS 1-49

MAINTENANCE INTERVALS 1-50

GENERAL RECOMMENDATIONS1-50

BUT THE OWNER'S MANUAL IS DIFFERENT? 1-50 BUT THE REPLACEMENT PART IS DIFFERENT?1-50

IS MY DRIVING "NORMAL" OR"SEVERE"? 1-50

COMPONENT LOCATIONS

UNDERHOOD MAINTENANCE COMPONENT LOCATIONS—R-SERIES 1-11

UNDERHOOD MAINTENANCE COMPONENT LOCATIONS—C-SERIES1-12

SPECIFICATIONS CHARTS

VEHICLE IDENTIFICATION CHART 1-8

GENERAL ENGINE SPECIFICATIONS 1-9

GASOLINE TUNE-UP SPECIFICATIONS1-31

RECOMMENDED LUBRICANTS1-36 MAINTENANCE SCHEDULES 1-51 CAPACITIES1-54

HOW TO USE THIS BOOK 1-2

TOOLS AND EQUIPMENT 1-2

SERVICING YOURVEHICLE SAFELY 1-4

FASTENERS, MEASUREMENTS

AND CONVERSIONS 1-5

SERIAL NUMBER IDENTIFICATION 1-7

AND TUNE-UP1-10

FLUIDS AND LUBRICANTS 1-35

TRAILER TOWING1-46

iTARTING A DEAD BATTERY 1-47

JACKING1-48

MAINTENANCE INTERVALS1-50

HOW TO USE THIS BOOK

This Chilton'sTotal CarCare manual for 1988-981/2,% and1ton Chevrolet and GMC Pick-ups, Blazers,Jimmys, Tahoes, Yukonsand Suburbans is intendedto help you learn more about the inner workingsofyourvehicle, while savingyoumoney on its upkeepand operation.

The beginning of the book will likely be referred to the most, sincethat is whereyouwillfind information for maintenance andtune-up. Theothersections deal with themorecomplex systems of your vehicle Systems (from engine through brakes)arecoveredto the extentthat the averagedo-it-yourselftrcan attempt This book will not explain such things as rebuilding adifferent! I becausetheexpertise required and thespecial tools necessarymake thi; uneco nomical Itwill, however, giveyou detailed instructionsto helpyouchan jeyour own brakepadsand shoes, replacespark plugs, and performmany morj jobs that cansaveyou money and help avoid expensive problems

Asecondary purpose ofthis book isareference for owners whowant to understandtheir vehicle and/or their mechanics better.

Where to Begin

Before removingany bolts, readthrough theentireprocedure This will give you the overall view of what tools and supplies will be required So read,ahead and plan ahead Each operationshould beapproached logicallyandall proce dures thoroughly understood beforeattempting anywork

If repairofacomponent is not considered practical,wetell you howb remove thepartandthen howto installthe newor rebuilt replacement l(ithis way,you at least save labor costs.

Avoiding Trouble

Many procedures inthis book require you to "label anddisconnect..." a group of lines, hoses or wires Don't bethink you can rememberwhere(very thinggoes—youwon't Ifyou hook up vacuum or fuel lines incorrectly,!he vehicle may run poorly, if atall Ifyou hook up electricalwiring incorrecly, you may instantly learnavery expensive lesson

Youdon't need to knowthe proper name for each hoseor line Apiedjof masking tapeonthe hose and apiece on its fittingwill allow youto ass jn your own label As long asyou remember your own code,the lines can berel on nected bymatching your tags. Remember that tapewill dissolve in gasaineor solvents; ifapart is to bewashed or cleaned, use another method of idq itifica tion. A permanent felt-tippedmarker or ametal scribe can beveryhand; for marking metal parts. Removeany tape or paper labels after assembly

Maintenance or Repair:

Maintenance includes routine inspections,adjustments,andreplacertentof parts which show signs of normal wear. Maintenance compensatesfor wsar or deterioration Repair implies that something has broken or is notworkinji A need for arepair is oftencaused by lack of maintenance, for example:ditlining and refillingautomatic transmission fluid is maintenance recommended it spe cific intervals Failureto do this can shorten the life ofthetransmission/ transaxle, requiringveryexpensive repairs While no maintenanceprogm.mcan prevent items from eventually breakingorwearingout, ageneral rule is|rue: MAINTENANCE IS CHEAPER THAN REPAIR

TOOLS AND EQUIPMENT

I SeeFigures 1thru 15

Without the proper tools andequipment it is impossible to properlyservice your vehicle Itwould bevirtually impossible to catalogevery tool that you would needto perform all of theoperations in this book Itwould beunwise for theamateur to rush out and buy anexpensivesetoftools onthetheory(hat he/she may needone or more of them at some time

The best approach is to proceed slowly, gathering agood quality set of those tools that are used most frequently Don't bemisled bythe low cost of bargain tools It is far better to spend a little more for betterquality Forged wrenches, 6 or 12-point sockets and fine tooth ratchets areby far preferable to their less expensive counterparts As any good mechanic cantell yoM,there arefewworse experiencesthantryingto work onavehiclewith badtorjls

Two basic mechanic's rulesshouldbementioned here First, wheneverthe left side of the vehicle or engine is referredto, it meansthe driver'sside Con versely, the right side of the vehicle means the passenger's side Second,screws and boltsareremoved byturningcounterclockwise, andtightened byturning clockwise unlessspecificallynoted

Safety is alwaysthe most important rule Constantly beawareofthedangers involved in workingon an automobile and takethe properprecautions Please refer to the informationin this section regarding SERVICING YOURVEHICLE SAFELY and the SAFETYNOTICEon the acknowledgment page

Avoiding the Most Common Mistakes

Payattentionto the instructions provided Thereare3 common mistakesin mechanical work:

1 Incorrect orderof assembly, disassembly or adjustment Whentaking something apart or putting ittogether, performing steps in thewrongorder usu ally just costsyou extratime; however,it CAN breaksomething Read theentire procedure beforebeginning. Perform everything in the order in which the instructions sayyou should, even if you can't seeareason for it Whenyou're takingapart something that is very intricate, you might want to drawapictureof how it lookswhen assembled in order to make sure you geteverything back in its proper position When making adjustments, performthem in theproper order. Oneadjustment possibly will affect another.

2 Overtorquing(or undertorquing) While it is morecommon for over tcrquing to cause damage, undertorquing may allowafastener to vibrateloose causing seriousdamage Especiallywhen dealing with aluminum parts,pay attention to torque specificationsand utilizeatorquewrench in assembly Ifa torque figure is not available, remember that ifyou areusing the right tool to performthe job,you will probably not have to strainyourself to getafastener tight enough. Thepitch of most threads is so slight thatthetension you put on thewrench will bemultiplied manytimes in actualforce onwhat youaretight ening

There aremany commercial products availablefor ensuringthatfasteners won't come loose, even ifthey are not torqued just right (averycommon brand is Loctite") Ifyou'reworried about getting something together tight enough to hold, but looseenough to avoid mechanical damageduringassembly,oneof trese products might offer substantial insurance. Before choosing athreadlock irg compound, read thelabel onthe packageandmake sure theproduct is compatible withthe materials,fluids, etc. involved.

3 Crossthreading This occurs when apartsuch asabolt is screwedinto a nutor castingatthewrong angleandforced. Crossthreading is more likelyto occur if access is difficult It helps to clean and lubricatefasteners, thento start threading the bolt, spark plug, etc with your fingers I!youencounter resis tance, unscrewthe partand start overagain at adifferentangleuntil itcan be irserted and turned severaltimes without mucheffort Keep in mindthat many parts havetaperedthreads,so that gentle turning will automaticallybring the part you'rethreadingto the proper angle Don't put awrenchon the part until it's been tightenedacouple ofturns by hand Ifyou suddenlyencounter resistance, and the part hasnot seatedfully, don't force it Pull it back out to make sure it's clean andthreadingproperly Besure to takeyour time and be patient, and alwaysplan ahead Allow your self ample time to performrepairsand maintenance frequently: thoseassoci careful to

• Jackstands(or support.

• Oilfilterwrench

• Spout orfunnel forpouring fluids

• Greasegunfor chassis lubrication (unless your vehicle is not equipped with anygrease fittings)

• Hydrometer forchecking thebattery(unless equipped with asealed, maintenance-free battery)

• Acontainer for draining oil andother fluids

• Ragsforwiping uptheinevitablemess

In addition to the above items thereareseveral othersthat are not absolutely necessary, but handy to havearound These include anequivalent oil absorbent gravel, likecat litter, and the usual supply of lubricants, antifreeze and fluids This is a basic list for routine maintenance, butonly your personal needs and desire canaccurately determine your list oftools

After performing afew projects on the vehicle,you'll beamazedatthe other tools and non-tools on your workbench Some usefulhousehold items are:a large turkey baster or siphon, empty coffeecansand icetrays (to storeparts),a

ball oftwine,electrical tapefor wiring, small rolls of coloredtape for tagging lines or hoses, markersand pens,a note pad, golf tees(for plugging vacuum lines), metal coat hangers or a roll of mechanic's wire (to hold things out of the way), dental pick or similar long, pointed probe,astrong magnet, and a small mirror (to seeinto recessesand under manifolds)

A more advanced setof tools, suitable for tune-up work, can bedrawn up easily While the tools areslightly moresophisticated, they need not be outra geously expensive There areseveral inexpensivetach/dwell meters on the mar ket that areevery bit as good for the average mechanic asa professional model Just besurethat it goes to a least 1200-1500 rpm on the tach scale and-that it works on 4, 6 and 8-cylinder engines Thekeyto these purchases isto make them with aneyetowards adaptability andwide range A basic list of tune-up tools could include:

• Tach/dwellmeter

• Sparkplug

• Feelergaugesforvalveadjustment

• Timing

The choice of a timing light should be made carefully A light which vorks on the DC current supplied by the vehicle's battery is the best choice; it mould have a xenon tube for brightness On any vehicle with an electronic ignit in sys tem, atiming light with aninductive pickup that clamps around theNo | spark plug cable is preferred

In addition to these basic tools, there are several other tools and gaut

• Compression gauge Thescrew-in type is slower to use, bute!imii(jates the possibility of a faulty reading due to escaping pressure

• Manifold vacuum gauge

• 12V test light.

• Acombination volt/ohmmeter

• Induction Ammeter This is used for determining whether or not thdre is current in awire These are handy for use if a wire is broken somewhere! na wiring harness

As a final note, you will probably find a torque wrench necessary for; II but the most basic work The beam type models are perfectly adequate, althd jgh the

SERVICING YOUR VEHICLE SAFELY

» See Figures 16,17 and 18

It is virtually impossible to anticipate all of the hazards involved with autt motive maintenance and service, but care and common sense will prevent most accidents.

The rules of safety for mechanics range from "don't smoke around gaioline," to "use the proper tool(s) for the job." The trick to avoiding injuries is to develop safe work habits and to take every possible precaution

• Do keep a fire extinguisher andfirst aid kit handy

• Dowear safety glasses or goggles when cutting, drilling, grinding ing, even if you have 20-20 vision If you wear glasses for the sake of v wear safety goggles over your regular glasses

newer click types (breakaway) are easier to use. The click type torque wrenches tend to be more expensive Also keep in mind that all types of torquewrenches should be periodically checked and/or recalibrated You will haveto decide for yourself which better fits your pocketbook, and purpose

Special Tools

Fig. 15 Proper information is vital, so always have a Chilton Total Car Care manual handy :syou may find useful These include:

Normally, the use of special factory tools is avoided for repair procedures, since these are not readily available for the do-it-yourself mechanic When it is possible to perform the job with more commonly available tools, it will be pointed out,but occasionally, a special tool was designed to perform aspecific function and should be used Beforesubstituting another tool, you should be convinced that neither your safety nor the performance of the vehiclewill be ccmpromised

Special tools can usually be purchased from an automotive parts store or from your dealer In some cases special tools may beavailable directly from the tool manufacturer

or pry sion,

• Do shield your eyes whenever you work around thebattery. Batteriescontain sulfuric acid In case of contact with, flush the area with water or a mixture of water and baking soda, then seek immediate medical attention

• Do usesafety stands (jackstands) for any undervehicle service Jacksare for raising vehicles; jackstands are for making sure the vehicle stays raised until you want it to come down

• Do useadequate ventilation when working with any chemicals or haz ardous materials Like carbon monoxide, the asbestos dust resulting from some brake lining wear can be hazardous in sufficient quantities

• Do disconnect the negative battery cable when working on the electrical system The secondary ignition system contains EXTREMELY HIGHVOLTAGE In some cases it can even exceed 50,000 volts

• Dofollow manufacturer's-directions whenever working with potentially hazardous materials Most chemicals and fluids are poisonous

Fig A variety of tools and gauges be used for spark plug gapping ina type timing light

Fig 13 vacuum/pressure tester is neces for many testing procedures

Fig. 12 A screw-in type compression gauge is recommended for compression testing

Fig. modern automotive multi meters incorporate many helpful features

• Doproperly maintain your tools Loose hammerheads, mushroomed punches and chisels, frayedor poorly grounded electricalcords,excessively worn screwdrivers, spread wrenches (openend), crackedsockets, slipping ratchets, or faulty droplight sockets can causeaccidents

• Likewise, keep your tools clean;a greasy wrench can slip off a bolt head, ruining the bolt and often harming your knuckles in the process.

• Do use the proper size and type of tool for the job at hand Do select a wrench or socket that fits the nut or bolt The wrench or socket should sit straight, not cocked

• Do, when possible, pull on awrench handle ratherthan push on it,and adjust your stance to prevent a fall.

• Do besure that adjustable wrenches aretightly closed on the nut or bolt and pulled so that the force is on the side of the fixedjaw

• Dostrike squarely with a hammer; avoid glancing blows

• Do setthe parking brake and block the drive wheels if the work requiresa running engine

Don'ts

• Don't run the engine in a garage or anywhere else without proper venti lation—EVER! Carbon monoxide is poisonous; it takes a long time to leave the human body and you can build up a deadly supply of it in your system by simply breathing in a little at a time You may not realizeyou are slowly poi soning yourself Always use power vents,windows, fans and/or open the garage door

• Don't work around moving parts while wearing loose clothing. Short sleeves are much safer than long, loose sleeves Hard-toed shoes with neoprene

FASTENERS, MEASUREMENTS AND CONVERSIONS

Bolts, Nuts and Other Threaded Retainers

» See Figures 19 and 20

Although there are a great variety of fasteners found in the modern car or truck, the most commonly used retainer is the threadedfastener (nuts, bolts, screws, studs, etc.) Most threaded retainersmay be reused, provided that they are not damaged in use or during the repair Some retainers (such as stretch bolts or torque prevailing nuts) are designed to deform when tightened or in use and should not bereinstalled

Whenever possible, we will note any special retainers which should be replaced during a procedure. But you should always inspect the condition of a retainer when it is removed and replace any that show signs of damage Check all threadsfor rust or corrosion which can increasethe torque necessaryto achieve the desired clamp load for which that fastenerwas originallyselected Additionally, be sure that the driver surfaceof the fastener has not been com promised by rounding or other damage In some cases a driver surface may become only partially rounded, allowing the driver to catch in only one direc tion In many of these occurrences, a fastenermay be installed andtightened, but the driver would not be able to grip and loosen the fasteneragain

If you must replace a fastener, whether due to design or damage, you must ALWAYS be sure to use the proper replacement In all cases,a retainerof the

soles protect your toes and give a better grip on slippery surfaces Watches and jewelry is not safeworking around a vehicle Long hair should be tied back under a hat or cap

• Don't use pocketsfor toolboxes A fall or bump can drive ascrewdriver deep into your body Even a rag hanging from your back pocket can wrap around a spinning shaft or fan

• Don't smoke when working around gasoline, cleaning solvent or other flammable material

• Don't smoke when working around the battery When the battery is being charged, it gives off explosivehydrogengas

• Don't usegasoline to wash your hands; there areexcellent soaps avail able Gasoline contains dangerous additiveswhich can enter the body through a cut or through your pores Gasoline also removes all the natural oils from the skin so that bone dry hands will suck up oil andgrease

• Don't service theair conditioning system unless you areequipped with the necessarytools and training When liquid or compressed gas refrigerant is released to atmospheric pressure it will absorb heat from whatever it contacts This will chill or freeze anything ittouches

• Don't usescrewdriversfor anything other than driving screws! A screw driver used as an prying tool can snap when you least expect it, causing injuries At the very least, you'll ruin a good screwdriver

• Don't usean emergencyjack (that little ratchet,scissors, or pantograph jack supplied with the vehicle)for anything other than changing a flat! These jacks are only intended for emergency use out on the road; they are NOT designed as a maintenance tool If you are serious about maintaining your vehi cle yourself, invest in a hydraulic floor jack of at least a 11/2ton capacity, and at least two sturdy jackstands

Fig

Fig

Fig.

Thread gauges areavailable to help measure a bolt or stud's thread. l|ost automotive and hardware stores keep gauges availableto help you selec the proper size Ina pinch, you can use another nut or bolt for a thread gauc; If the bolt you are replacing is not too badly damaged, you can select a match iy finding another bolt which will thread in its place Ifyou find a nut which threads properly onto the damaged bolt, then use that nut to help select he replacement bolt

Be aware that when you find a bolt with damaged threads, you may also find the nut or drilled hole it was threaded into has also teen damaged. If this is the case, you may have to drill and tap thd hole, replace the nut or otherwise repair the threads. NEVER try to I irce a replacement bolt to fit into the damaged threads

Torque

Torque is definedasthe measurement of resistance to turning or rotat ig tends to twist a body about an axis of rotation. A common example of thi would betightening a threaded retainer such as a nut, bolt or screw Mee ;uring torque is one of the most common ways to help assure that a threadedretainer has been properlyfastened.

When tightening a threaded fastener, torque is applied in three distinc areas, the head, the bearing surface and the clamp load About 50 percent of thi mea sured torque is used in overcoming bearing friction This is the friction b tween the bearingsurfaceof the bolt head, screw head or nut face and the base nater ial or washer (the surfaceon which the fastener is rotating) Approximate 140 percent of the applied torque is used in overcoming thread friction This laves only about 10 percent of the applied torque to develop a useful clamp IDE i (the force which holds ajoint together) This means that friction canaccount 'pr as much as 90 percentof the applied torque on afastener.

TORQUE WRENCHES

I See Figure 21

In most applications, a torque wrench can be used to assure proper installa tion of afastener Torque wrenches come in various designs and most auDmo tive supply stores will carry avariety to suit your needs Atorque wrench should be used any time we supply a specific torque value for a fastener Again, the general rule of "if you are using the right tool for the job, you should not have to strain to tighten a fastener" applies here

Beam Type

The beam type torque wrench is one of the most popular types It cons sts of a pointer attached to the head that runs the length of the flexible beam (srpft) to a scale located near the handle. As the wrench is pulled, the beam bends fnd the pointer indicatesthetorque using the scale

Click (Breakaway) Type

Another popular design of torque wrench is the click type Tousethe click type wrench you pre-adjust it to atorque setting Oncethe torque isreached, the wrench has a reflex signaling feature that causes a momentary breakawayof the torque wrench body, sending an impulse to the operator's hand

Pivot Head Type

I SeeFigure 22

Some torque wrenches (usually of the click type) may beequipped with a pivot head which canallow it to be used in areas of limited access. BUT, it must be used properly To hold a pivot head wrench, grasp the handle lightly, and as you pull on the handle, it should be floated on the pivot point Ifthe handle comes in contact with the yoke extension during the process of pulling, there is a very good chance the torque readings will be inaccuratebecause this could alter the wrench loading point. The design of the handle is usually such asto make it inconvenient to deliberately misuse the wrench

••It should be mentioned that the use of any U-joint, wobble or extension will have an effect on the torque readings, no matter what type of wrench youare using Forthe most accurate readings, install the socket directly on the wrench driver. If necessary, straight extensions (which hold a socket directly under the wrench driver) will have the least effect on the torque reading. Avoid any extension that alters the length of the wrench from the handle to the head/driving point (such as a crow's foot). U-joint or wobble extensions can greatly affect the readings; avoid their useat all times.

Rigid Case (Direct Reading)

A rigid case or direct reading torque wrench is equipped with a dial indicator to show torque values Oneadvantage of these wrenches is that they can be held atany position on the wrench without affecting accuracy Thesewrenches are often preferred because they tend to be compact, easy to readand havea great degreeof accuracy.

PIVOTED used

TORQUE ANGLE METERS

Because the frictional characteristics of eachfastener or threaded hole will vary, clamp loads which are based strictly on torquewillvary aswell In most applications, this variance is not significant enough to causeworry But, in certain applica tions, a manufacturer's engineers may determinethat more preciseclamp toads are necessary (such is the casewith many aluminum cylinder heads) Inthesecases,a torque angle method of installation would bespecified When installingfasteners which aretorqueangle tightened, a predetermined seatingtorque and standard torque wrench are usually used firstto removeany compliance from the joint. The fastener isthen tightened the specifiedadditional portion of aturn measured in degrees. A torqueangle gauge (mechanical protractor) is used for these applications.

Standard and Metric Measurements

» See Figure 23

Throughout this manual, specificationsaregiven to help you determine the condition of various components on your vehicle, or to assist you in their installation. Some of the most common measurements include length (in. or cm/mm), torque (ft. Ibs., inch Ibs. or Nm) and pressure (psi, in. Hg, kPa or mm Hg). In most cases, we strive to providethe proper measurement as determined by the manufacturer's engineers

Though, in some cases, that value may not beconveniently measured with what is available in your toolbox Luckily, many of the measuring devices which are available today will have two scalesso the Standard or Metric measure ments may easily be taken If any of the various measuring tools which are available to you do not contain the same scale as listed in the specifications, use the accompanying conversion factors to determine the proper value

The conversion factor chart is used by taking the given specificationand multiplying it by the necessary conversionfactor For instance, looking at the first line, if you have a measurement in inches such as "free-play should be2 in." but your ruler reads only in millimeters, multiply 2 in by the conversion factor of 25.4 to get the metric equivalent of 50.8mm Likewise, if thespecifica tion was given only in a Metric measurement, for example in Newton Meters (Nm), then look atthe center column first Ifthe measurement is 100 Nm, multi ply it by the conversion factor of 0.738 to get 73.8 ft Ibs

LENGTH-DISTANCE

Cubic (in3)

IMP Quarts (IMPqt ) x 1.137

IMP Gallons (IMP gall x 4..S46

IMP Quails (IMP qt.) < 1.201

IMP Gallons (IMP gal.) x 1.201 Ounces x 29.573

US Pints (US pi > x .473 Quarts (US 4i ) x .946 Gallons (US g.,1.) x 3 7X5

MASS-WEIGHT

Ounces (oz I * 28.35 (Ib.) x 454

PRESSURE

Pounds Pe Sq In

On V8 gasoline engines, the engine identification number is usually f pnd on a machined padon the block, atthefront just below the right side cylind head Theengine identification number is sometimes also found on a mat hined pad on the left, rear upper side of the block, wherethe engine mates with he bellhousing

On V8 diesel engines, the engine identification number is found ona machined pad on the front of the block, betweenthe left cylinder head anf the thermostat housing, and/or on a machined pad on the left rearof the bloc)t, just behind the leftcylinder head In the followingexample,engine number F1210TFA is broken down asfollows: F—Manufacturing Plant. F-Flint andT-Tonawanda

12—Month of Manufacture (December) 10-Day of Manufacturer (Tenth) engine and Engine Combination

Transmission

The Muncie 117mm 4-speed transmission is numbered on the rear of the case, abovethe output shaft

The 4-Speed 85mm and 5-Speed 85mm transmissions are numbered on the right rear of the case.

The NVG3500 5-speed transmissions are numbered on the top, leftside of the case, near the bellhousing

The NVG4500 5-speed transmissions are numbered on the top, left side of the case, near the bellhousing

The NVG 5LM60 5-speed transmissions are numbered on the lower left side, about halfway back on thecase.

The automatic transmissions are identified by a plateattachedto the right side, which is stamped with the serial number

Drive Axle

The drive axle serial number is stamped on the axle shaft housing, whereit connects to the differential housing

Front axles on four wheel drive models are marked on the front of the left axle tube

Transfer Case

All transfercases havea build tag attached to the case

On the NP205, it is attachedto the bolt retaining the Power Take Off(PTO) cover

Onthe NP231, NP233 and NP241, it is attached to the rearcase half On the NV241 and NV243, it is attached to the rear case half Onthe Borg Warner 4401/4470, it is attached to an extension housing bolt

Service Parts Identification Label

I See Figure 27

The service parts identification label, commonly known asthe optio i list, is usually located on the inside of the glove compartment door On sor IB trucks,you mayhave to look for it on an inner fender panel Thelabel ists the vehicle serial number, wheelbase, all Regular Production Options (IPOs) andall special equipment Probably, the most valuable pieceof inform tion on this label isthe paint code, a useful item when you have occasion tj need paint

ROUTINE MAINTENANCE AND TUNE-UP

Proper maintenanceand tune-up is the key to long and trouble-freev :hicle life Studies haveshown (hat aproperly tuned and maintained vehicle a \e better gas mileage than an out-of-tune vehicle As a conscientio s

and look through thefilter atthe light If no glow of light can beseenthrough the element material, replace the filter If holes inthe filter element are apparent or signs ofdirt seepage through the filter areevident, replacethe filter

owner anddriver, setasideaSaturday morning,sayonce amonth,to cf ick or replace items which could cause major problems later Keep your own p rsonal logtojot down which services you performed, howmuch theparts cost m, the date, andthe exactodometer reading atthe time. Keep all receiptsfo such items as engine oil and filters, so that they may be referred to in case ofjelated problems orto determine operating expenses.As ado-it-yourselfer, the:i receipts aretheonly proof you have thatthe requiredmaintenancewas[ in formed Intheevent of awarranty problem, these receiptswill be invalua;)le

The literatureprovidedwithyour vehicle when itwas originally delivered includes the factoryrecommended maintenance schedule Ifyou no Ion; ;rhave this literature,replacement copies are usually available from thedealer

Air Cleaner

» See Figures 28, 29 and 30

The element should be replaced atthe recommended intervalsshown in the Maintenance Intervalschart later in this section Ifyour truck is operated under severely dusty conditionsor severe operatingconditions, more frequent changes will certainlybe necessary Inspect the element at leasttwicea\tear Early spring andearly fall arealwaysgood times for inspection. Remove tie element and checkfor any perforations or tears inthe filter Checkthecli aner housing tor signs of dirt or dust that may have leakedthrough the filter e ement or in through the snorkeltube. Position adroplight on one side of theelement

Fig.