Diploma in Differentials: Backlash, Preload and Crown Wheel Setup
Online postgraduate diploma of 800 hours in differentials: backlash, preload and crown wheel setup. 8 modules covering the differential unit, disassembly and metrology, pinion depth, bearing preload, backlash and contact pattern, limited-slip differentials and final verification, with an assigned technical tutor.
Diploma in Differentials: Backlash, Preload and Crown Wheel Setup — studying from New Zealand
Regulation, safety and reliability engineering is well established in New Zealand, underpinned by a strong regulatory framework for health and safety, transport, building and electrical equipment. WorkSafe New Zealand administers workplace health and safety law, while Standards New Zealand develops and publishes national standards. Professionals in this area support compliance, certification and risk assessment for manufacturers, infrastructure operators and public agencies.
Fees for New Zealand: NZ$2,960 (New Zealand dollar), with instalments and employer sponsorship available.
Relevant bodies in New Zealand
Typical roles
Questions from New Zealand
Which New Zealand bodies set the rules for safety and compliance engineering?
WorkSafe New Zealand regulates workplace health and safety, and the NZ Transport Agency Waka Kotahi handles vehicle and transport compliance. Engineering New Zealand is the professional body, including the Chartered Professional Engineer pathway. SEIUM's qualifications are private and not accredited by any national body, so their recognition is decided by employers or the relevant body.
Do New Zealand employers hire RAMS and safety engineers?
Yes. Reliability, availability, maintainability and safety roles exist across infrastructure, energy, transport, and manufacturing. Employers typically look for demonstrated competence against recognised standards and professional registration where relevant. A private qualification can support an application, but employers decide how much it counts.
Can I study this alongside work, and do I need a visa?
Yes to both parts. The programme is 100% online and taught in English, so no student visa is needed to study from New Zealand. You get an assigned technical tutor and complete a final project. Fees are payable in instalments, and employer sponsorship is possible. Programme lengths range from 300 to 1,900 hours.
Take the controls.
Run a real engineering trade-off from this field. Move the sliders, watch the model react in real time and beat the challenge.
What you will be able to do
Understand how the differential unit works and how it fails.
Disassemble and measure components with metrological rigour.
Set pinion depth using shims.
Establish the correct bearing preload.
Set backlash and interpret the contact pattern.
Rebuild limited-slip differentials.
Verify the unit after assembly and running-in.
Who it's for
- Transmission technicians looking to deepen their expertise in differential setup.
- Classic car restoration mechanics who rebuild rear axles and final drives.
- Motorsport mechanics preparing differentials for competition.
- Differential specialists who want a structured method for shimming and pattern reading.
- Mechanical workshop managers responsible for transmission work.
- Test bench technicians who verify drivetrain units.
- Engineering or science graduates seeking to enter classic vehicle restoration.
What you'll work with
- ISO 1328-1 (accuracy of cylindrical gears)
- ISO 10300 (calculation of load capacity of bevel gears)
- ISO 23509 (bevel and hypoid gear geometry)
- SAE J306 (viscosity of gear lubricants)
- API GL-5 (gear lubricant classification)
- KISSsoft
- Autodata
- Haynes Pro
- Excel shim calculation spreadsheet
- Romax
8 modules
1.1Function of the differential and final drive ratio1.2Hypoid and spiral bevel gears1.3Crown wheel, pinion and planet gears1.4Loads on gear teeth and bearings1.5Lubrication of hypoid gears1.6Rigid-axle and independent differentials1.7Plate-type and Torsen limited-slip differentials1.8Characteristic noises and their diagnosis1.9Wear and typical failures1.10Case study: diagnosing a whine in a rear axle
2.1Disassembly sequence for the unit2.2Marking of parts and shims2.3Inspection of gear teeth and wear patterns2.4Measurement of bearings and housings2.5Inspection of the casing and its alignment2.6Measurement of planet gear end float2.7Use of dial indicators and micrometers2.8Recording initial measurements2.9Deciding whether to reuse or replace2.10Practical: disassembly and measurement of a rear axle
3.1Concept of pinion depth3.2Factory dimensions and pinion markings3.3Pinion depth tools3.4Calculation of setting shims3.5Fitting pinion bearings3.6Effect of depth on the contact pattern3.7Common setting errors3.8Variations between manufacturers3.9Recording the final setting3.10Workshop: shim calculation with a pinion depth gauge
4.1Pinion preload with a collapsible spacer4.2Preload with solid shims4.3Measuring rolling torque with a torque gauge4.4Preload of the differential carrier bearings4.5Casing spread and its measurement4.6Effect of temperature on preload4.7Consequences of excessive or insufficient preload4.8Tightening torques for nuts and bolts4.9Final preload check4.10Practical: preload setting with a collapsible spacer
5.1Definition of gear backlash5.2Measurement with a dial indicator at several points5.3Adjustment using adjuster nuts or side shims5.4Marking compound and its application5.5Interpreting patterns on the drive and coast sides5.6Heel and toe corrections5.7Influence of backlash on noise5.8Manufacturer tolerances5.9Documenting the final pattern5.10Workshop: backlash setting and pattern reading
6.1Types of mechanical limited-slip differentials6.2Friction plates and spring preload6.3Ramps and locking percentage6.4Rebuilding a plate-type limited-slip differential6.5Measuring breakaway torque6.6Lubricants and friction modifiers6.7Limited-slip differentials in historic motorsport6.8Torsen and helical differentials6.9Diagnosing worn limited-slip differentials6.10Practical: rebuilding a plate-type limited-slip differential
7.1Cleaning the casing and components7.2Final assembly with controlled torques7.3Gaskets and oil seals7.4Oil filling and levels7.5Bench noise test7.6Running-in the crown wheel and pinion7.7Road test and thermal check7.8Inspection after running-in7.9Recommendations to the owner7.10Case study: verifying a unit after running-in
8.1Selection of the axle for study8.2Diagnosis of noises and failures8.3Complete disassembly and metrology8.4Shim calculation8.5Preload and backlash setting8.6Validation of the contact pattern8.7Running-in and verification plan8.8Budget and timings8.9Report and presentation8.10Final project: final review with the tutor
How you'll learn
Training is 100% online on the SEIUM campus, with downloadable material, recorded classes and an assigned technical tutor. There are no fixed timetables: you progress at your own pace within each intake, so the programme fits around your work.
Each module combines theory, guided reading of the original standard and applied exercises. The working software is KISSsoft, Autodata, Haynes Pro, a shim calculation spreadsheet in Excel and Romax, in free, academic or evaluation versions. Tests are studied using real procedures: backlash setting with a dial indicator, contact pattern reading with marking compound and rebuilding of plate-type limited-slip differentials. Assessment is continuous by module, plus the final project.
Standards covered: ISO 1328-1, ISO 10300, ISO 23509, SAE J306, API GL-5.
Build it end to end
Your final project follows the real engineering workflow, step by step, reviewed by your tutor.
Where this takes you
Requirements
- Prior technical training or professional experience in the sector. No university degree is required.
- Internet connection and a computer capable of running the programme software.
- English sufficient to read technical standards.
Ready to start?
Send your application today. Our admissions team replies within 72 hours with your study plan and funding options.
Frequently asked questions
The programme totals 800 hours over 6–8 months. You set your own pace within each intake, and your tutor helps you plan the workload around your job.
You work with KISSsoft, Autodata, Haynes Pro, an Excel shim calculation spreadsheet and Romax, using free, academic or evaluation versions. Your tutor indicates the free alternative wherever one exists.
A SEIUM Institute diploma, awarded on passing the continuous assessment and the final project. It is SEIUM's own qualification, not an official state degree; its recognition depends on the programme completed and the regulations of each country.
Yes. Modules passed are recognised in a higher programme in the same area (postgraduate diploma or master's). Ask about the recognition policy when you enrol.
Prior technical training or professional experience in the sector (no university degree required), a computer able to run the software and English sufficient to read technical standards.
Start dates are set by SEIUM's faculty for each intake. Our admissions team will confirm the next available date when you apply.
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