Audi Audi A4 2017-present Drivetrain Bolt Torque Specifications
This page provides detailed torque specifications for various drivetrain bolts on the 2017 to present Audi A4, including transmission, driveshaft, and differential components.
Important Information
Safety guidelines and reference information for proper torque application
Safety First
- Always verify torque specifications with your vehicle's factory service manual
- Use properly calibrated torque wrenches
- Replace all torque-to-yield (TTY) bolts - they are single-use only
- When in doubt, consult a professional mechanic
Quick Reference Guide
Quick Reference Guide
Common Torque Patterns
Star Pattern
Used for wheels and other circular bolt patterns
Cross Pattern
Used for gaskets and cover plates
Sequential Pattern
Used for head bolts and other critical components
Common Mistakes to Avoid
Common Mistakes to Avoid
Over-tightening
Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.
Always use a calibrated torque wrench and follow specifications exactly.
Incorrect Torque Sequence
Tightening bolts in the wrong order can cause uneven pressure distribution and potential leaks or damage.
Follow the manufacturer's specified torque sequence pattern.
Dirty Threads
Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.
Clean and inspect all threads before assembly. Use new thread locker if specified.
Reusing TTY Bolts
Torque-to-yield bolts are designed to stretch and must not be reused.
Always replace TTY bolts with new ones. They are single-use only.
Dry vs. Lubricated
Not accounting for whether torque specs are for dry or lubricated fasteners can lead to incorrect tension.
Check if specs are for dry or lubricated threads. Use specified lubricant when required.
Recommended Tools
Recommended Tools
Torque Wrench (1/4" Drive)
Torque Wrench (3/8" Drive)
Torque Wrench (1/2" Drive)
Angle Gauge
Torque Wrench Care
- Calibrate annually or after 5,000 clicks
- Store at lowest setting
- Keep clean and lubricated
Search Specifications
Search by component name, bolt size, or description
Torque Calculator
Convert between different torque units
Drivetrain Flywheel
Torque specifications for flywheel attachment to crankshaft.
1 Flywheel Bolts
M12 x 1.25
Flywheel Bolts
M12 x 1.25Torque Value
Important Notes
Drivetrain Transmission
Torque specifications for transmission mounting and related components.
1 Transmission Mounting Bolts
M12 x 1.75
Transmission Mounting Bolts
M12 x 1.75Torque Value
Important Notes
2 Transmission to Engine Bolts
M12 x 1.75
Transmission to Engine Bolts
M12 x 1.75Torque Value
Important Notes
3 Transmission Oil Pan Bolts
M8 x 1.25
Transmission Oil Pan Bolts
M8 x 1.25Torque Value
Important Notes
4 Transmission Fluid Drain and Fill Plugs
M18 x 1.5
Transmission Fluid Drain and Fill Plugs
M18 x 1.5Torque Value
Important Notes
5 Transmission Fluid Drain/Fill Plug (Separate)
M18 x 1.5
Transmission Fluid Drain/Fill Plug (Separate)
M18 x 1.5Torque Value
Important Notes
Drivetrain Axles
Torque specifications for axle, half shaft and CV joint components.
1 Drive Axle/Half Shaft Bolts
M10 x 1.5
Drive Axle/Half Shaft Bolts
M10 x 1.5Torque Value
Important Notes
2 CV Joint/Axle Nut
M24 x 2.0
CV Joint/Axle Nut
M24 x 2.0Torque Value
Important Notes
Drivetrain Driveshaft
Torque specifications for driveshaft and related components.
1 Propeller/Drive Shaft Bolts
M10 x 1.25
Propeller/Drive Shaft Bolts
M10 x 1.25Torque Value
Important Notes
2 Driveshaft Center Support Bearing Bolts
M8 x 1.25
Driveshaft Center Support Bearing Bolts
M8 x 1.25Torque Value
Important Notes
Drivetrain Differential
Torque specifications for differential mounting and fluid maintenance.
1 Differential Mounting Bolts
M14 x 1.5
Differential Mounting Bolts
M14 x 1.5Torque Value
Important Notes
2 Differential Drain/Fill Plug
M18 x 1.5
Differential Drain/Fill Plug
M18 x 1.5Torque Value
Important Notes
Drivetrain Transfer Case
Torque specifications for transfer case mounting and fluid maintenance.
1 Transfer Case Mounting Bolts
M14 x 1.5
Transfer Case Mounting Bolts
M14 x 1.5Torque Value
Important Notes
2 Transfer Case Drain/Fill Plug
M18 x 1.5
Transfer Case Drain/Fill Plug
M18 x 1.5Torque Value
Important Notes
Troubleshooting Guide
Common issues, diagnostic steps, and prevention guidelines
Common Issues
Bolt stretching, stripped threads, uneven torque patterns
Common Issues
Bolt stretching, stripped threads, uneven torque patterns
Loose Components
Symptoms:
- Rattling or vibration noises
- Visible movement in components
- Uneven panel gaps
Solutions:
- Clean threads and mounting surfaces
- Replace damaged fasteners
- Apply proper torque in sequence
- Use thread locker if specified
Stripped Fasteners
Symptoms:
- Unable to achieve proper torque
- Fastener spins freely
- Visible thread damage
Solutions:
- Use thread repair kit if appropriate
- Install thread insert (HeliCoil)
- Replace component if threaded hole is damaged
- Upgrade to higher grade fastener if recommended
Overtightened Components
Symptoms:
- Cracked or deformed parts
- Broken fasteners
- Compressed gaskets or seals
Solutions:
- Replace damaged components
- Use new fasteners
- Follow proper torque sequence
- Verify correct torque specifications
Diagnostic Steps
Visual inspection, torque verification, thread assessment
Diagnostic Steps
Visual inspection, torque verification, thread assessment
Visual Inspection
Inspect the affected area for any visible signs of damage or wear
- Check for cracks or deformation
- Look for signs of excessive wear
- Verify proper fastener installation
Torque Verification
Verify the torque applied to the fasteners
- Check the torque wrench calibration
- Verify the torque specification
- Compare the applied torque to the specification
Thread Assessment
Assess the condition of the threads
- Check for signs of thread damage
- Verify the thread type and size
- Check for proper thread engagement
Prevention Guidelines
Best practices, maintenance tips, tool care
Prevention Guidelines
Best practices, maintenance tips, tool care
Best Practices
- Always follow the recommended torque specification
- Use the correct type and size of fasteners
- Verify the torque wrench calibration regularly
Maintenance Tips
- Regularly inspect the affected area for signs of wear or damage
- Replace damaged or worn-out components promptly
- Keep the work area clean and organized
Tool Care
- Regularly clean and maintain the torque wrench
- Store the torque wrench in a dry and secure location
- Verify the torque wrench calibration before each use
Frequently Asked Questions
Find answers to common questions about torque specifications
Q1 Why is it important to use the correct torque specifications?
Why is it important to use the correct torque specifications?
Using the correct torque specifications ensures proper clamping force, preventing bolts from loosening due to vibration or thermal expansion. Under-torquing can lead to component failure, while over-torquing can stretch or break bolts, causing damage and potential safety hazards. For example, insufficient torque on the driveshaft bolts could cause excessive play and eventual failure, while over-torquing them could damage the threads or the bolts themselves.
Q2 What type of lubricant should be used on drivetrain bolts?
What type of lubricant should be used on drivetrain bolts?
Typically, new or dry bolts are not recommended. Many fasteners require a specific lubricant or anti-seize compound. When specified, it is usually an oil or an anti-seize compound designed for use with threaded fasteners. Some bolts are torque-to-yield and should be replaced once they are loosened and not reused. Always consult the manufacturer's service manual for the specific requirements of your vehicle and bolt type, otherwise dry fasteners are fine.
Q3 What tools are needed to correctly torque drivetrain bolts?
What tools are needed to correctly torque drivetrain bolts?
You will need a calibrated torque wrench that is capable of measuring the specified torque values, sockets or wrenches of the correct size and type, and possibly an extension or universal joint to reach tight areas. It is best to use a torque wrench that is in the middle of its operational range for accuracy. Ensure the torque wrench has a current certification for best results.
Q4 How often should drivetrain bolts be checked for proper torque?
How often should drivetrain bolts be checked for proper torque?
Generally, drivetrain bolts should be checked whenever a component is removed or replaced. It's also recommended to check critical bolts (like those on driveshafts or differential mounts) after initial installation and after approximately 500 miles of driving to ensure they haven't loosened. Regular inspection during routine maintenance is also recommended.
Q5 What is 'torque-to-yield' and how does it affect bolt replacement?
What is 'torque-to-yield' and how does it affect bolt replacement?
'Torque-to-yield' (TTY) bolts are designed to stretch slightly beyond their elastic limit when tightened. These bolts should always be replaced when removed and never reused. They are commonly used in high-stress areas of the drivetrain. Attempting to re-use a TTY bolt can compromise its clamping force and could lead to failure. For example, many driveshaft flange bolts are torque-to-yield and should only be tightened to specified amount ONE time.
Environmental Considerations
Temperature, humidity, and seasonal effects on torque specifications
Temperature Effects
Includes: High Heat, Cold Weather, Thermal Cycling
Temperature Effects
Includes: High Heat, Cold Weather, Thermal Cycling
Temperature can significantly impact torque values and fastener behavior
Cold Weather
Effects:
- Increased material brittleness
- Higher torque required due to thread contraction
- Reduced thread lubricant effectiveness
Recommendations:
- Allow components to warm to room temperature when possible
- Consider using winter-grade thread lubricants
- Check torque values more frequently during winter months
Hot Weather
Effects:
- Thermal expansion of components
- Decreased friction in threads
- Accelerated lubricant breakdown
Recommendations:
- Check torque when components are at normal operating temperature
- Use temperature-resistant thread lockers
- Consider re-torquing after heat cycles
Humidity and Corrosion
Covers: Rust Prevention, Salt Exposure, Moisture Control
Humidity and Corrosion
Covers: Rust Prevention, Salt Exposure, Moisture Control
Moisture and corrosion can affect fastener integrity and torque values
High Humidity
Effects:
- Accelerated corrosion formation
- Reduced friction coefficient
- Potential thread seizing
Prevention:
- Use corrosion-resistant fasteners
- Apply appropriate anti-seize compounds
- Maintain proper protective coatings
Salt Exposure
Effects:
- Rapid corrosion development
- Thread damage
- Seized fasteners
Prevention:
- Regular underbody washing
- Use of sacrificial anodes where appropriate
- Application of protective coatings
Seasonal Maintenance
Spring, Summer, Fall, and Winter maintenance schedules
Seasonal Maintenance
Spring, Summer, Fall, and Winter maintenance schedules
Spring
- Inspect for winter damage
- Clean and protect exposed fasteners
- Check torque on critical components
Summer
- Monitor heat-affected components
- Check expansion-related loosening
- Inspect cooling system mounts
Fall
- Prepare for winter conditions
- Apply corrosion protection
- Verify all fasteners are properly torqued
Winter
- More frequent inspection of critical fasteners
- Check for salt damage
- Monitor suspension component torque
Related Resources
Tools, service procedures, and technical bulletins
Recommended Tools
Torque Wrench (1/2 inch drive)
A calibrated torque wrench is essential for accurately tightening bolts to the specified torque values. A 1/2 inch drive is suitable for most drivetrain components.
- Calibrated for accuracy
- Audible click when torque is reached
- Suitable for a range of torque values
Torque Wrench (3/8 inch drive)
A 3/8 inch drive torque wrench is useful for smaller bolts and areas where a 1/2 inch wrench might be too large.
- Calibrated for accuracy
- Audible click when torque is reached
- Suitable for lower torque values
Socket Set (Metric)
A comprehensive set of metric sockets is required to fit various bolt head sizes found on the Audi A4 drivetrain.
- Various sizes to fit different bolts
- Durable construction
- Impact rated optional
Extension Bars
Extension bars are needed to reach bolts in recessed or hard to access areas.
- Various lengths for different needs
- Strong construction
- Multiple drive sizes
Universal Joint
A universal joint allows torque application at an angle, useful for bolts that are not directly accessible.
- Allows angled torque application
- Durable construction
- Various drive sizes
Service Procedures
Front Axle Driveshaft Bolt Replacement and Torque
This procedure covers the removal and installation of the front axle driveshaft and the required torque of the bolts.
- Loosen the wheel bolts.
- Raise the vehicle and remove the wheel.
- Remove any retaining clips or bolts holding the drive shaft.
- Carefully remove the drive shaft.
- Install the new drive shaft and bolts.
- Tighten the driveshaft bolts to the specified torque value (typically 70 Nm + 90 degrees).
- Install the wheel and lower the vehicle.
- Tighten the wheel bolts to the specified torque.
Rear Differential Mounting Bolt Torque
This procedure outlines the tightening of the bolts holding the rear differential to the chassis and subframe.
- Locate the rear differential mounting bolts.
- Clean the bolt threads if necessary.
- Begin tightening the bolts in a star pattern to avoid uneven pressure.
- Tighten the rear differential mounting bolts to the specified torque (typically 100 Nm + 90 degrees).
- Verify all bolts are properly tightened.
Transmission Mount Bolt Torque
This procedure covers the torque of transmission mount to the chassis.
- Locate the transmission mount bolts.
- Clean the bolt threads if necessary.
- Begin tightening the bolts in a star pattern to avoid uneven pressure.
- Tighten the transmission mount bolts to the specified torque (typically 60 Nm + 90 degrees).
- Verify all bolts are properly tightened.
Technical Service Bulletins
Drivetrain Vibration Issues
2018-05-15Some 2017-2018 Audi A4 models may experience drivetrain vibration due to incorrectly torqued driveshaft bolts.
Resolution: Re-torque the driveshaft bolts to the specified torque value of 70 Nm + 90 degrees. Ensure that the bolts are installed correctly and are not damaged. Inspect all associated mounts and bushings.
Rear Differential Noise
2020-11-20A whining noise from the rear differential may be caused by loose mounting bolts or damaged mount. Check torque and condition.
Resolution: Re-torque the rear differential mounting bolts to 100 Nm + 90 degrees. Inspect differential mount bushing.
Transmission Mount Failure
2022-02-10A clunk or vibration can be felt on acceleration which can be caused by a failed transmission mount. Check mount and torque of the mount bolts.
Resolution: Check and torque the transmission mount bolts to 60 Nm + 90 degrees. Inspect the transmission mount and replace if necessary.
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Technical Information
- All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
- Vehicle specifications and procedures may vary by model year, trim level, and region.
- Always follow the manufacturer's recommended procedures and safety precautions.
- Working on vehicles can be dangerous. Always take proper safety precautions and use appropriate safety equipment.
- If you're unsure about any procedure, consult a qualified professional mechanic.