precision truck training · page 3 tmi precision truck training dodge trucks d 2 introduction...

Course IDodge Trucks

Second Edition— April, 2002

By James E. Godfreyand Robert J. Godfrey

TMI Career-builder training byTruck Marketing Institute

PrecisionTruck

TrainingTechnical & Product Trainingfor the Dodge Sales Consultant

TMI Precision Truck Training Dodge Trucks

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Introduction

ForewordIt is exciting to know that you have taken a step into the world of lightduty trucks with your enrollment in Precision Truck Training: Course I.

This is a short, five lesson distance education course written by pro-fessionals who want you to be comfortable when you talk truckswith your customers. When you finish, you’ll know the Dodge Truckmodel line, the basics of distributing loads on trucks, importanttruck terms, and where to find information in your Dodge TruckSales Consultant Product Guide—your Product Guide as we'll call itthroughout your lessons.

It doesn’t matter if you make a living selling trucks or work for a leas-ing company or fleet that is buying them. This course is designed forthe beginner who thinks the term “fifth wheel” refers to a spare tire.

Please start right now by finishing the introductory section. It containsgood information on what the course is, how to study and submit tests,and what the standards are for receiving a Certificate that can be framedfor your wall!

The investment you make now with this course gives you knowledge tolast a lifetime! Welcome to Precision Truck Training: Course I andgood luck as you move through each of the five lessons.

Sincerely yours,

Robert J. GodfreyDirector

PS: When you finish the course, please complete the short questionnaireat the end of the Introduction section (pages 15-16). Your opinions areimportant and help us design better training courses!

Dodge Trucks Precision Truck Training TMI

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IntroductionPage 4

ContentsIntroduction 3 Foreword

4-6 Contents7 Objective: Being a Truck Professional7 Summary of Lessons8 Truck Marketing Institute: A History9 How to Study Effectively

10 “What if I Get Stumped?”11 Taking the Tests11 What is Passing? What is a Good Score?12 Six Month Enrollment Term12 Employer Follow-Up12 To Mail or to Fax?13 Group Study Policy14 Score Card15 Course Evaluation Survey

Lesson 1: 17 The Light Truck Market18 Truck Popularity: Why?19 Light Truck Categories24 Incomplete Vehicles & Documentation25 Chassis Drive Types26 “Just Give Me a Half-Ton Truck!”26 Getting Acquinted:

Dodge Truck Sales Consultant Product Guide28 Engineering/Technology28 Product Presentation: “The Three-Minute Drill”29 Embrace the Dodge System: Sell Professionally30 Your Product Line: Quick Reference30 Cabs, Bodies and Wheelbases31 Wheelbases and Cab-Axle Dimensions31 Three Minutes with The Dodge Durango31 Mission Accomplished


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Introduction

Lesson 2: 33-34 The Product Guide: Phase 234 Your Secret Weapon: Job Rating35 Curb Weight Defined36 Truck Weight Ratings39 Calculating Equipped Curb Weight40 Accounting For Occupant Weights41 Allowed Payloads and Cargo Loads41 Calculating GVW—Gross Vehicle Weight42 Forms: Job Rating Worksheets42 Coming Attractions: Weight Distribution43 Basic Truck Dimensions44 Interior / Exterior Trim45 Trim Levels: From Base/WS to Laramie SLT45 Dodge Truck Package Groups47 The E&T Review: Electrical and Steering46 Electrical System Basics48 Your Three-Minute Drill: Dakota Pickups

Lesson 3: 49-55 Truck Weight Distribution56 Understanding Load Capacity

56-58 Frame Strength59 Frames and Special Bodies59 Axles and Axle Systems61 Rear Axle Information62 Springs and Spring Ratings63 Shock Absorbers and Stablizer Bars63 Tires and Wheels63 Radial versus Bias Ply Construction64 Tire Tread Designs65 Tire Load Ratings

65-66 Tire Sizes and Dimensions66-67 Brake Systems

67 E&T Review: Brakes68 Three Minute Drill: Ram Pickups69 Gross Axle Weight Ratings69 P-Metric tires: Your Need to Know70 Equipment Weights


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IntroductionPage 6

Lesson 4: 71 Engine Considerations for Light Trucks72 Fuel Types Available72 Naturally Aspirated vs. Turbocharged73 Carburetion versus Fuel Injection73 Diesel versus Gasoline Types74 Truck Owners: The Performance X-Factor74 Back to Basics: Torque75 Engine Power Depends on Torque76 More Power Basics: Horsepower77 Axle Ratios and Performance78 Low versus High Axle Ratios79 Transmissions: Making it Happen

80-82 Transmissions: Manual and Automatic82 Power: Where does it Go?

84-88 Truck Peformance: Trailer Towing89 Harnessing the Horsepower90 Power Robbers; Heat and Alititude90 Three Minute Drill: Ram Chassis-Cab

Lesson 5: 91 Evolution of 4x4s: Remember the Power Wagon92 4x4 Basics93 4x4 Variations94 Locking Hubs and Differentials94 Ram Wagons: Distributing the Weight95 GVW, GTW and GCW97 Trailer Tongue Weight Distribution97 Load Distribution: Dead Weight Hitch98 Weight Distributing Hitches99 Four Trailer and Hitch Classes

100 What About Towing Capacity?101 Trailering Power Demands and the X-Factor101 Fifth Wheel Trailer Hitches102 Towing Fifth Wheelers: Gross Weight Factors103 PTO: What is it?104 Dump Trucks: Defining the Limits105 Chassis-Cabs: Guide to Body Combinations107 Diesel Engines: Power for Tough Jobs108 Diesels: They Don’t Perform Miracles!108 How Much Will a Diesel Save?109 Vocations for Diesel Power110 Trucks, Safety and the Environment110 Product Guide Reviews111 Three-Minute Drill:

Ram Wagons, Vans and Conversions112 It’s Cross Roads Time


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Introduction

Introduction

Objective: Being a Truck ProfessionalWhether you sell trucks or operate trucks for a living, you will bemore successful if you can listen to your customers, find out whattheir needs are, and then give them choices that reflect your profes-sional experience.

Helping to establish your credibility as a truck professional isthe objective of Precision Truck Training: Course I. Through thiscourse, you will find that your confidence has increased becauseyou’ve got a good dose of truck fundamentals filed away for use whenyou need it.

The truck market is huge and the buyers are many and different.Overall, however, they buy trucks because they perceive trucks willdo something for them that cars can’t. So, selling “professionaly”means that YOU can recommend the right truck for the right buyer,the first time, and every time!

Summary of LessonsThe objective of Precision Truck Training: Course I is summarized bythe previous paragraph. To achieve that total objective, we have splitthe course into five lessons, covering a variety of subjects, each withits own objectives. Here is a summary of what each lesson is about:

Lesson 1. Understanding the truck market. Why is there value intrucks? What are the basic truck model types and where do Dodgetruck models fit in. How are Dodge truck models identified? Do “tonratings” mean anything? What’s a 4x4, 4x2, or an AWD? Where iswhat in your Product Guide?


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IntroductionPage 8

Lesson 2. More in-depth training with your Product Guide. WhyGAWR, GVWR and payload capacities are important; your intro-duction to the Dodge Truck Job-Rating system. How to calculatepayload capacity. What are the significant truck dimensions?

Lesson 3. How to distribute payloads to the front and rear axles.What are the important frame types and ratings? What are the dif-ferent types of front and rear axles and their suspensions? How areaxle weight ratings calculated and why are they important? Whatare the different types of tires and how much can they carry?

Lesson 4. Describe the basic types of engines used and the differ-ent fuels they operate on. What is a turbocharger? Explain the dif-ference between torque and horsepower, and be able to figure howmuch power is needed. How do axle ratios affect performance? Howto express performance in gradeability terms.

Lesson 5. A focus on 4x4s—Durango, Dakota and Rams. What isa 4x4 and how does it compare to all wheel drive? Trailering: Whatdo the trailering terms GCW, GTW, and tongue weight mean? Whatare load distributing and ball hitches? Chassis-cab applications. Die-sel power: What are the markets for diesels? How fast can the extrainvestment pay off.

Truck Marketing Institute: A HistoryTruck Marketing Institute (TMI) was founded in 1964 to producespecialized training courses for those who sell and operate trucks.Historically, we have taught students the terminology and the ba-sics of how to recommend the one best truck for the job at hand.

TMI is a privately owned school that operates in cooperation withthe leading truck manufacturers. We strive to develop up-to-date cor-respondence courses and those manufacturers endorse them as “fac-tory approved training.”

Truck Marketing Institute is an accredited mem-ber of the Distance Education and Training Coun-cil. You can be assured that, as an accredited mem-ber, we meet these rigid guidelines: Qualifiedfaculty and staff. Careful admission screening. Rea-sonable tuition. Courses that have educational value.

Lesson One Page 17


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LESSON 1Lesson ObjectivesThis is the place to start your foundation of knowledge about how tospec light duty trucks, and it really doesn’t matter if you’ve everworked with trucks before!

The objectives of this lesson are quite basic. You need to appre-ciate the huge size of the light truck market, know the different typesof trucks, and understand the Dodge offerings in this market place.By the time you have completed this lesson and worked through theopen book test, you should have achieved these objectives:

� Understand the size of the light truck market� Appreciate the value people see in trucks� Identify the basic categories of truck models� Match Dodge truck models with the categories� Reach a familiarity with the Dodge lineup� Explain why ton ratings have little significance� Tell the difference between two-wheel, four-wheel, and all-wheel drive� Familiarization with the Dodge Truck Sales Consultant Product Guide.

Before reading any further, round up your Product Guide and have itready when we make reference to it. You’ll find it especially helpfulonce we get into explaining the different vehicle types.

The Light Truck MarketIndustry-wide, where cars and trucks are sold side-by-side, truckstypically account for over 60% of sales. For Dodge, the impact oftrucks is more pronounced: in a typical year, trucks average about75% of Dodge dealer deliveries. Light trucks are big business!

According to Automotive News, the 2000 calendar year showsthere were over 8.4 million light trucks sold in North America. Here

Lesson One


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with a second bench seat, can accommodate up to six adults. DodgeRam is your full size pickup, available in regular cab or Quad Cabversions. Available bodies are the nominal 6.25- and 8.0-ft full widthboxes (know as the short and long boxes). Yet another choice comes:2-wheel or 4-wheel drive (4x2 or 4x4).

Compact Pickups are another important segment of the market. Theyare smaller in size and have less load capacity, but they usually sellfor less and typically cost less to operate than the full size pickups.Dodge Dakota is your strong competitor in this field of smaller pick-ups. The Dakota, as you will find, has significant advantages of size,capacity and engine choices: 4-cylinder, V6 and V8 options. The ClubCab and regular cabs come with a 6.5-ft box. But what’s more, youcan offer 2-wheel or 4-wheel drive. And focus on the spacious 4-doorQuad Cab with its 5.25-ft box!

Compact Sport Utility Vehicles, by their broad popularity, brought acommon abbreviation into the English language: SUV, or SUVs inthe plural form. Here again, as with compact pickups, you can takepride in your offering of the Dodge Durango. As influenced by mar-ket demands, the Durango comes as a 4-door model. Sharing its front-end sheet metal with the Dakota, as well as common chassis compo-nents, you’ll find the Durango to be larger in size than its compactSUV counterparts—Chevrolet TrialBlazer, Ford Explorer and GMCEnvoy. Where there is a choice of 2- or 4-wheel drive for an SUV, the

DakotaQuad Cab

Lesson Two


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LESSON 2Lesson ObjectivesMuch as Lesson 1 made your aware of the different types of Dodgetrucks, this lesson will take you deeper into your Product Guide insearch of more detailed information. Here is a list of the objectiveswe have set forth in Lesson 2. Once you have studied this lesson andhave completed Test 2, you should have a clear understanding of:

� Product Guide format and contents� What the terms GVW and GVWR mean� What is meant by the term GAWR� How vehicle curb weight is determined� Where to find curb weights in the Product Guide� Likewise, where to find optional equipment weights� How to determine payload capacity� Your secret weapon: Job-Rating� Common vehicle dimensions and abbreviations� Determining interior /exterior trim content� Making use of equipment packages� Electrical system basics.

The Product Guide: Phase 2Through your studies in Lesson 1, you gained a basic familiarity withthe Product Guide. There was an examination of its content, sectionby section, attention was devoted to the Durango in particular, as wellas the assigned Engineering /Technology topics. It is time now to getinto the specifics of truck model data, how it is organized and pre-sented. As you can see by the stated lesson objectives, we are aimingmainly at truck weights, ratings and load capacities. For this purpose,your focus will center on the Ram pickup models. Spread out yourProduct Guide to the Ram 1500 Pickup section, Page 1 with its Tableof Contents: There is the key to finding it all, from the Three MinuteDrill to Technical Specifications. It’s also worth noting, that the se-quence of presentation is largely consistent for other model sections.

Lesson Two


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that the weights of other options must be accounted for, just as yousaw in the example leading up to the Equipped Curb Weight. Thentoo, you have the driver and passenger weights to factor in. When putinto the form of simple equations, these will lead directly to allowedpayload and allowed cargo weights:

GVWR minus Equipped Curb Weight equals Allowed PayloadAllowed Payload minus Occupants’ Weight equals Allowed Cargo Weight

With the procedure at hand, let’s put some numbers together, continu-ing with the Ram 2500 pickup example. We arrived at an EquippedCurb Weight of 5629 pounds, and the Quad Cab seats up to six per-sons, so six at 150 each comes to 900 pounds for occupants. But whatis the published GVWR for this Ram 2500 pickup? Where else butthe Job-Rating table, which shows a GVWR of 8800 pounds. Nowwe can stack the figures for subtraction in two steps:

Gross Vehicle Weight Rating 8800 lbsLess: Equipped Curb Weight – 5629

Equals: Allowed Payload 3171 lbs

Less: Occupants, 6 x 150 – 900Equals: Allowed Cargo Weight 2271 lbs

Calculating GVW— Gross Vehicle WeightYes, GVW was defined a few pages back, but let’s revisit GVW witha set of numbers. And for this purpose we can stick with the Ram 2500pickup example, including its allowed cargo weight of 2271 pounds.What you see here is a shifting of the elements of the cargo weightequation:

Equipped Curb Weight + Occupants + Cargo = GVWRam 2500: Equipped Weight 5629 lbs

Plus: Occupants, 6 x 150 900Plus: Cargo Weight 2271

Equals: Gross Vehicle Weight 8800 lbs

Equiped Curb Weight + Occupants + Cargo = GVW

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Lesson Three Page 49

LESSON 3Lesson ObjectivesIn Lesson 2, you gained insight into vehicle and axle weight rat-ings, as well as an understanding of payload ratings. Lesson 3 takesa different approach as we look at the truck from a mechanical stand-point, considering the springs, axles, tires, wheels and brakes. Wealso get into distributing payloads and option weights using percent-ages. Completion of this lesson and the test will enable you to:

� Distribute weights using percentages� Use load CGAs to calculate distribution percentages� Compare the terms yield strength and section modulus� Define Resisting Bending Movement—RBM� Understand the different types of front axle systems� Explain the difference between semi-floating and full-floating axles� Interpret tire sizes and load ratings� Understand and explain tire pressure affects on load capacity� Explain the basics of spring ratings, shock absorbers and stabilizers� Calculate GAWRs based upon given component ratings

Truck Weight DistributionIt would be just as well if you have had no prior experience with theaspect of truck technology that we call weight distribution. All toooften, this very elementary subject is approached with a mixture ofwitch doctor mumbo-jumbo and mind-bending arithmetic. At thispoint, clear your memory and start fresh!

Just what is truck weight distribution? The clearest verbal defi-nition would be the sharing of weight by the front and rear axles ofthe vehicle. Trucks, cars, bicycles, little red wagons — they all con-form to the same principles of weight proportioning to the axles.


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Lesson ThreePage 56

Understanding Load CapacityThus far, the approach to truck load capacity has been limited toend results: the truck weighs this much, the rated gross weight isthat much, and the cargo capacity is roughly the difference betweenthe two. With that knowledge as a base, plus weight distribution knowhow to boot, you are in good position to examine the load carryingcomponents of light trucks. One of the key components to vehiclecapacity is the truck frame.

Frame Strength Means Truck StrengthA truck can be no stronger than its frame. Yet, all too frequently thatbasic truth is violated by those who overload trucks or “beef” themup with oversize springs, tires and wheels. Trucks may be built witha separate cab on chassis (such as your Dakota pickup) or may gofor a frame that becomes an integral part of the body, like the Cara-van. Let’s now take a look at the separate cab and frame type.

Looking down from a bird’s eye position, truck frames usually takeon a ladder like appearance, leading to the term “ladder” type frame.The two lengthwise pieces are called side rails or “side members” whilethe lateral pieces that connect the side rails are called “crossmembers.”

Light trucks can have either channel or box section type framerails, similar to the two line drawings that follow. The only differenceis that the box section takes a channel style rail and closes in the fourthside. Box sections, when used, are typically found in the front axleand cab area, but sometimes back of the cab in the load area—as is thecase of the hydroformed boxed side rails where used for Dodge frames.

Dimensions usually are expressed in terms of the depth (D) andwidth (W) of the outside channel dimensions plus the thickness (T)of the rail material. Lighter trucks will have frames with smallerdimensions and thinner frame material thanheavier models. Vehicles with inte-gral frames will not haveframe dimensionspublished.

Ladder Frame

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Lesson Three Page 65

Tire Load RatingsA review of either your Product Guide or TMI appendix tire informa-tion will reveal that tires are rated in load carrying capacity. The loadcapacity of a tire depends on the basic strength of the tire and howmuch air pressure (psi) is contained. Thus, a tire inflated to 50 psi willhave a lower capacity load rating than the same tire inflated to 80 psi.

Tire ratings depend on the carcass construction. A stronger car-cass will have a greater “load range” or “ply rating” than will a lessercarcass. Thus, a tire with load range “E” can handle higher loadsthan one of load range “D.” The higher load range allows the tire tobe inflated to a higher psi for a greater capacity.

Tires also come with “single” and “dual” use ratings. Single usemeans a rating for two tires per axle, while dual use is for those axleswhich use four tires. Tire makers give duals a lower rating per tirethan singles for safety reasons. They believe that with crowned roads,a set of duals should not be counted on to carry as much weight astwo widely spread tires on a front axle.

Tire Sizes and DimensionsMost light truck tires are metric sized and grouped into either “P-met-ric” or “LT-metric” types. The “P” type stands for passenger car basedtires while the “LT” tires are light truck oriented tires. Here are two ex-amples that illustrate the size designations for both the tire and the wheel.

P235 / 75 R 15 / SLP-Metric (Passenger Type Tire)

Section Width: 235 mmAspect Ratio: 75

Construction: Radial PlyWheel Diameter: 15 inches

SL: Standard Load (XL Extra Load)

LT 225 / 75 R 16 / DLT-Metric (Light Truck Tire)

Section Width: 225 mmAspect Ratio: 75

Construction: Radial PlyWheel Diameter: 16 inches

Load Range: D

Lesson Four Page 71


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LESSON 4Lesson ObjectivesAs you move through this course, we trust that you are developinga clear understanding of trucks in general, and Dodge trucks in par-ticular. In this lesson, we take a look at one more decision factor fortruck buyers, and that relates to how much performance the truckshould have.

Listening to what customers say about what they are looking forin a truck is a very important role for you, the truck professional.You need to be on the lookout for the performance oriented buyer.Who is that? It could be the horse trailer puller, it might be the fireor rescue squad, or it just may be that average person looking for aneight-passenger Ram Wagon. The customer who talks about goingup hills, starting on grades, getting out of mud or sand, or pullinglarge loads clearly is talking about performance ability.

By working through this lesson and completing the test, youshould be able to achieve the following objectives:

� Know the basic types of engines available in Dodge trucks� Name four types of fuels for spark ignited engines� Explain the function of a turbocharger� Tell the difference between torque and horsepower� Review the available manual and automatic transmissions� Explain how axle ratios affect performance and economy� Calculate power demands for light trucks� Express performance in terms of gradeability

In dealing with truck performance ability in Lesson 4, you willsee that horsepower cares not whether it comes from gasoline ordiesel fuel, and the same applies to torque output. This indicates ahint that you may experience a diesel performance example. But thatsaid, Lesson 5 will offer more about diesels and their uses.

Engine Considerations for Light TrucksThe engines in current usage fall into several different design types:Inline 4- and 6-cylinder, plus 6, 8, and 10-cylinder V-types, each ab-

Dodge Trucks Precision Truck Training TMID 2

Lesson FourPage 78

Does the higher numerical axle ratio multiply the available horse-power? The answer is a big NO! Horsepower cannot be multiplied,but it can be shifted by changing the engine operating speed at a givenroad speed. Of course, that assumes that the engine puts out morepower with an increase in engine speed. That is typically the casefor light truck engines.

Low versus High Axle RatiosIn selling light trucks, it is unlikely that you will need to calculate en-gine speeds, road speeds or required axle ratios. If you are interestedin that data, or if you have a particularly tough customer, refer to Table1 in the Appendix. At this point, what we want to do is establish a clearunderstanding of the effect of axle ratios on performance and economy.Contrast the roles of our 3.07 and 3.73 axle ratios.

A Low Numerical Ratio of 3.07 to 1:� Is considered “fast” because road speed is

relatively fast for a given engine rpm� Will reduce engine rpm at a given road speed� Tends to reduce engine power output� Will reduce vehicle starting capability� Can result in improved fuel economy.

A High Numerical Ratio of 3.73 to 1:� Is considered “slow” because road speed is slow for a given rpm� Increases engine speed and power at a given road speed� Increases overall vehicle performance, including startability� Will tend to result in increased fuel consumption.

Performance Trade-offsSo which would be better for pulling a heavy camper? Would yourecommend a smaller engine with a high axle ratio or would you gofor the large displacement engine and a low axle ratio because it candevelop its power at a lower rpm? Well, both solutions may be sat-isfactory for your customer.

Take a look at how the truck is going to be used. An ambulanceconstantly loaded to 10,000-lbs GVW running 25,000 miles a yearis likely to be a candidate for your biggest V8 because it needs the


Lesson FourPage 90

under Table 1B tell how to deal with gears other than direct drive.Example: recall the direct-drive rpm of 2443; multiply that by the0.75 ratio and out comes 1832 rpm. Also, divide the direct-drive2700-rpm speed (60.8 mph) by each gear ratio and you’ll arrive atthe geared speeds shown by this shift pattern chart. But that’s as faras we are going here; this is not about chart making.

The Power Robbers: Heat and AltitudeGuess what? Thanks to a turbocharged diesel under the hood, ourRam 3500 dodged two factors that can rob engine power: Hot in-take air and high elevations. Recall that engines are tested at 77°Fwith barometric pressure equal to 500-ft elevation. But for each 1,000feet higher, naturally-aspirated engines lose from 3% to 4% output(the lesser for diesels and fuel-injected gasoline). But turbochargedengines shine, typically giving full power to 7,500 feet and beyond.

As for temperature: Colder, more dense air enhances output,while hotter air degrades by about 1% per 10°F above 77° F. Again,turbocharged engines are barely affected. So what to do about it?Be concerned if extremes exist, like desert heat or high mountaintravel. Think bigger engine, or hey, a turbocharged 5.9L Cummins!

Your Three-Minute Drill: Ram Chassis-CabsHere’s that question again: “Why should I buy a Dodge Ram Chassis-Cab?” Get to know those key talking points under the headings of Safety,Utility, Value, Performance, Styling and New Features. Learn about themarket too, with the understanding that every new chassis-cab gets a spe-cial body of one kind or another. So check back on those Ram 2500-3500dimensions, starting with the cab–axle lengths: 56, 60 and 84 inches.Know the CAs like your middle name! Consider also that you have 4x4chassis versions to offer whenever traction is a vital issue. And finally,keep that range of engine choices in mind—gasoline V8 or V10, or theCummins 5.9L turbo diesels. You’ve got a lot going for you; make it pay!

This concludes the textbook portion of this lesson. Review as

needed, and make sure you have studied each assigned part of

the Product Guide. Then, using this lesson and the Product Guide

as references, complete both sides of the test and mail or fax it

to 1-805-684-2868 for grading and a prompt reply.

Lesson Five


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LESSON 5Lesson ObjectivesFour down and one lesson to go. You’re in the home stretch! Most ofthe heavy topics are behind you, so this lesson will focus on the spe-cialty aspects of light trucks. These days, anyone connected with trucksneeds to have a clear understanding of 4x4s and 4-wheel drive sys-tems, and that is ahead for your taking. Recreational truck uses is an-other specialty, so there is more to know about trailer towing. Youhave a fine line of trucks featuring the optional Cummins diesel, andknowing its features, advantages and diesel cost aspects will be toyour benefit. And finally, to be an effective contender in the marketfor working trucks, know your chassis-cab potentials. Help is aheadfor you. Here is a summary of the objectives for this lesson:

� Know your Dodge 4x4 models and 4x4 drive systems� For truck-trailer combinations, determine gross weights� Understand GVW, GTW and GCW for trucks with trailers� Identify trailer and hitch classes� Know the hitch types, including fifth wheelers� Know your chassis-cab models and their potentials� Understand the markets for diesel powered trucks� Calculate diesel cost savings and the payback period� Be aware of advances in safety and a cleaner environment.

Evolution of 4x4s: Remember the Power Wagon!Looking back, the predecessors of DaimlerChrysler Corporation werepioneers in the development of all-wheel drive trucks. Out of WorldWar II came the world renowned Jeep 4x4, Dodge-built 4x4 troopcarriers and ambulances (aka “meat wagons”), and that unique 4x4

Lesson FivePage 96


about to be hitched together. And, following the diagram and sum-mary of the truck and trailer weights, you see the weight factors thatresult in the GVW of the 2500 Ram Wagon less the trailer hitch load.

Truck Model: Ram 2500 Wagon, 127" WB, 8-passengerEngine/Transmission: V8 / 4-speed automatic

Axle Ratings: 4,000-lb front / 5,740-lb rearAxle Ratio: 4.10:1 (Spicer 60)

Tires: LT 225 / 75R16-D front, single rearRatings (lbs): 7800-GVWR, 13,500-GCWR, 3880/4670-GAWRs

Weight Distribution (lbs) % Front Front Rear TotalBase Curb Weight, as above 3,065 2,113 5,178Tow Pkg & Selected Options 13 129 142Equipped Curb Weight 3,078 2,242 5,320Occupants, front (2) 76% 228 72 300Occupants, middle (3) 47% 212 238 450Occupants, rear (3) 21% 94 356 450Stowage Allowance – 10% – 62 682 620Truck GVW, less Trailer 3,550 3,590 7,140

Add 660 lbs of trailer tongue load to the 7,140-lb truck GVW and itmakes exactly 7,800 lbs GVW, matching the 7,800-lb GVWR. Thekey to that match is the “stowage allowance,” an amount workedbackward from the intended maximum GVW of 7,800 lbs includ-ing the trailer tongue load. More to follow, but first, let’s deal withtrailer hitches.

Summary:GVW 7,140GTW 5,600GCW 12,740

4940 660 3590 3550GTW: 5600 GVW: 7140

GCW: 12,740 lbs

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Lesson FivePage 108


Diesels: They Don’t Perform Miracles!Perhaps you have seen what some call “hot shot” truckers who tryto pull a 30-ft freight trailer using a light-duty truck with the big-gest available gas engine or a light-truck diesel. Loaded to about40,000 pounds GCW, either engine is doomed to a short life. Op-erators like that believe that they can defy the odds, and ignore therealities of gross weight ratings as determined and designated bythe engine supplier as well as the truck manufacturer. The moral:abide by the Dodge Job-Rating Charts.

Your Job-Rating Charts are a quick and complete reference toavailability of the Cummins 5.9L turbocharged diesels throughoutthe Dodge truck line. Summarizing, you have the option of a dieselengine for each of the 2500 and 3500 series pickups and chassis-cabs, 4x4 as well as 4x2 models. As you observed in Lesson 4, this5.9L I-6 diesel engine can take you all the way to 20,000 poundsGCWR while maintaining superior open-highway performance. And,you want to recognize that there is a choice of heavy-duty transmis-sions to handle the high torque of the diesel engine, 5- or 6- speedoverdrive manuals or the 4-speed overdrive automatic.

How Much Will a Diesel Save?To sell diesel power, you can demonstrate that the operator will savemoney over the life of the truck. Show the savings by figuring howmany miles it will take for a “payback” of the net extra cost of thediesel engine over comparable gas engine power. Here is an exampleof such a comparison.

Truck Type: Ram 3500 chassis-cab—12-ft van bodyGVWR: 11,000 lbsEngine: Cummins 5.9L diesel versus gas V8

Mileage: 30,000 miles per yearPremium: $3,000 extra for diesel option (net*)Fuel Use: 18 mpg diesel versus 10 mpg gasFuel Cost: $1.26/gal diesel versus $1.20/gal gas

Ownership: 5 years, to trade-inResale Value: $1,600 premium versus gas

*Net premium: $4,600 initial extra less $1,600 resale extra

Appendix


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AppendixTABLES & DATA

Appendix Page 114 Weights and Measures / Metric Equivalents

115 Tires: Load and Inflation Data

116 Table 1A: “P-Metric” Tire-Axle Ratio Combinations

117 Table 1B: Light Truck Tire-Axle Ratio Combinations

118 Table 2: Rolling Resistance Net Horsepower Required

118 Table 3: Frontal Areas of Light-Duty Trucks

119 Table 4: Air Resistance Net Horsepower Required

119 Table 5: Grade Net Horsepower Required

120 Table 6: Road Surface Effects on Performance

121-124 Glossary: Light Truck Terms

Index Page

125-128 Index: Alphabetical References

Appendix


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Table 4: AIR RESISTANCE NET HORSEPOWER REQUIREDVehicle Speed mph (km/h) 40 64 45 72 50 81 55 89 60 97 65 105 70 113

Net HP Requiredper sq ft .341 .486 .667 .889 1.151 1.463 1.829

NET HP REQUIRED30 10.2 14.6 20.0 26.7 34.5 43.9 54.936 12.2 17.4 24.0 32.0 41.4 52.7 65.940 13.7 19.4 26.7 35.6 46.0 58.6 73.144 15.0 21.3 29.3 39.1 50.7 64.3 80.448 16.3 23.3 32.0 42.7 55.2 70.2 87.752 17.8 25.2 34.7 46.2 59.9 76.1 95.056 19.1 27.2 37.3 49.8 64.4 81.9 102.360 20.4 29.1 40.0 53.3 69.0 87.8 109.764 21.8 31.1 42.7 56.9 73.7 93.7 116.968 23.2 33.0 45.3 60.4 78.2 99.4 124.272 24.6 35.0 48.0 64.0 82.9 105.3 131.676 25.9 36.9 50.6 67.6 87.4 111.2 138.980 27.3 38.9 53.4 71.1 92.1 117.0 146.384 28.6 40.8 56.0 74.7 96.7 122.9 153.688 30.0 42.8 58.7 78.2 101.3 128.7 161.092 31.4 44.7 61.4 81.8 105.9 134.6 168.396 32.8 46.7 64.0 85.3 110.5 140.4 175.9

(Table allows for 10% driveline frictional loss.)

Table 5: GRADE NET HORSE POWER REQUIRED(NET HORSEPOWER REQUIRED FOR EACH PERCENT GRADE)

Vehicle Speed mph km /h 40 64 45 72 50 81 55 89 60 97 65 105 70 113

HP per 1000 LBS 1 1.185 1.333 1.482 1.630 1.778 1.926 2.074NET HP REQUIRED 2

6,000 lbs 2,722 kg 7.1 8.0 8.9 9.8 10.7 11.6 12.48,000 3,629 9.5 10.7 11.8 13.0 14.2 15.4 16.6

10,000 4,536 11.8 13.3 14.8 16.3 17.8 19.3 20.712,000 5,443 14.2 16.0 17.8 19.6 21.3 23.1 24.914,000 6,350 16.6 18.7 20.7 22.8 24.9 27.0 29.016,000 7,258 19.0 21.3 23.7 26.1 28.4 30.8 33.218,000 8,165 21.3 24.0 26.7 29.3 32.0 34.7 37.320,000 9,072 23.7 26.7 29.6 32.6 35.6 38.5 41.5

1 Multiply Net HP shown by grade percentage (times 5 for 5% grade, as an example).Table allows for 10% driveline loss.

2 For weights other than shown, divide gross weight by 1000 andmultiply by the HP per 1000 pounds.

Example: 9000 Pounds GVW at 55 mph.9000 ÷ 1000 = 9.9 x1.630 = 14.7 HP.

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Appendix


D 2

GLOSSARY OF LIGHT-DUTY TRUCK TERMS

AIR INJECTOR REACTOR Reduces unburned hydrocarbons and carbon monoxide toallowed levels by pressure injection of fresh air at exhaustports; oxygen ignites unburned hydrocarbons.

ALTERNATOR Alternating Current electrical generator; a diode rectifier,integrally-mounted or separate, changes output to directcurrent for vehicle electrical system.

AMMETER An instrument that indicates current flow in amperes,either discharging (-) of the battery, or charging (+) of thebattery by the generator.

AUXILIARY SPRINGS Secondary spring for rear axle; takes effect upon heavyloading. Also known as helper springs.

AXLE, FULL FLOATING See Lesson 3.

AXLE, HYPOID See Lesson 3.

AXLE, SEMI-FLOATING See Lesson 3.

AXLE RATIO See Gear Ratio. Also see Lesson 3.

BBC Distance from front bumper to back of cab.

BORE The diameter of an engine cylinder.

CAB-OVER (CAMPER) Extension of camper body over the truck cab. “Cab-over”trailer has a similar bunk projection over the tongueassembly.

CAB-OVER (TRUCK) Short BBC design; cab is over the engine.

CA DIMENSION Distance from back of cab to centerline of rear axle.

CARGO WEIGHT Combined weight of all loads, gear and supplies on avehicle-car, truck or trailer.

CATALYTIC CONVERTER Positioned in exhaust system between exhaust manifoldand muffler, catalytic converter changes carbon monoxideand unburned hydrocarbons into carbon dioxide and water.

CE DIMENSION Frame length, from back of cab to end of frame.

CG (Center of Gravity) The weight center or balance point, of an object-truck, body, a passenger, cargo or item ofequipment. The symbol for CG is:

CLOSE-RATIO (Transmission) In terms of their numerical ratios, gear ratios are closelystepped. These ratios are typical of a close-ratio 5-speedtransmission: First-4.03; Second-2.33; Third-1.38; Fourth-1.00; Fifth-0.75; Reverse-3.57.

COE See Cab-over (Truck)

COMPRESSION RATIO In a reciprocating piston engine, the ratio of cylindervolume at Top Dead Center divided by volume at BottomDead Center of the piston’s stroke.

IndexPage 128


D 2

SSafety equipment 21, 44, 110

Section modulus 57, 58, 60, 124

Semi-floating axle 61

Shock absorbers 63

Short wheelbase 30, 58

Spark ignition 72

Sport utility vehicle (SUV) 19, 21dimensions 22

Spring ratings 38, 39, 62

Stabilizer bars 63

TTare weight 39, 40, 105

equiped curb weight 104

"Three-quarter ton truck" 26

Tireload ratings 39

Tire-axle ratio combinations 116, 117

Tires 63, 72, 93, 115, 120, 123, 124aspect ratio 66capacity at max inflation 115illustration of parts of the tire 66load rating 65P-metric 65, 69rolling resitance 83size designations 65, 66sizes and dimensions 65–66tread designs 64tread type 124

Tongue load capacity 18, 96, 97

Tongue weight 97, 124distribution 97

Torque 71, 74–75, 79, 80, 124and diesel engines 108and engine speed 89curve 75

Torque converter 79, 81

Torsion bar suspensions 62

Total Payload 42

Towing capacity 100–101

Track (tread width) 43

Traction control 67

Trailer towing 94, 95, 96, 97, 98, 99,100, 101, 110

Transfer case 92, 103, 105

Transmissions 79, 82, 124automatic 81–82close ratio 80, 121heavy duty 108manual 80–81overdrive 101PTOs 103

Tread design 64

Turbochargers 72, 124and diesel engines 73and intercoolers 73less loss to altitude and heat 90

Twin I-Beam I.F.S. 60

Two-stage rear springs 62

Two-wheel drive 25

WWeight distributing hitches 98–99

Weight distribution 49, 50, 52, 53, 55,96, 97, 102, 104, 106, 124

cargo weight 42

Wheel spin 62

YYield strength 57, 58

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