Audi Audi S6 2018-present Drivetrain Bolt Torque Specifications & Fastener Values
Audi Audi S6 2018-present

Audi Audi S6 2018-present Drivetrain Bolt Torque Specifications

Detailed torque specifications for all drivetrain bolts on the 2018-Present Audi S6 (C8) platform, including transmission, driveshaft, and differential components.

Updated

Important Information

Safety guidelines and reference information for proper torque application

Quick Reference Guide
ft-lbs → Nm
× 1.356
ft-lbs → kg-m
× 0.138
Nm → ft-lbs
× 0.738
in-lbs → ft-lbs
× 0.083

Common Torque Patterns

Star Pattern

Used for wheels and other circular bolt patterns

Star Pattern torque pattern diagram showing proper bolt tightening sequence
Cross Pattern

Used for gaskets and cover plates

Cross Pattern torque pattern diagram showing proper bolt tightening sequence
Sequential Pattern

Used for head bolts and other critical components

Sequential Pattern torque pattern diagram showing proper bolt tightening sequence

Common Mistakes to Avoid

Over-tightening

Exceeding the specified torque value can stretch or break fasteners, damage threads, or crack components.

Prevention:

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.

Prevention:

Follow the manufacturer's specified torque sequence pattern.

Dirty Threads

Dirt, rust, or old thread locker can affect torque readings and proper fastener tension.

Prevention:

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.

Prevention:

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.

Prevention:

Check if specs are for dry or lubricated threads. Use specified lubricant when required.

Recommended Tools

Torque Wrench (1/4" Drive)

Range: 2-25 ft-lbs
Small fasteners, delicate components

Torque Wrench (3/8" Drive)

Range: 10-100 ft-lbs
Most common automotive fasteners

Torque Wrench (1/2" Drive)

Range: 30-250 ft-lbs
Large fasteners, wheels

Angle Gauge

Torque-to-yield (TTY) bolts

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

Transmission

Torque specifications for various components of the transmission, including mounting, case, and internal parts. These values ensure proper sealing, alignment, and function.

1

Transmission Mount Bolts (to Chassis)

M12 x 1.75
Torque Value
33 ft-lbs (45 N·m)
Important Notes
Secures the transmission to the chassis. Ensures proper drivetrain alignment and stability. Torque to spec to avoid vibration or mount failure. Value estimated based on similar Audi models.
2

Transmission to Engine Bolts

M12 x 1.5
Important Notes
Joins the engine and transmission bellhousing. Torque-to-yield bolts must be replaced each time they are removed. Ensure correct clamping force and prevents leaks. Value estimated based on similar Audi models.
3

Transmission Pan Bolts (Automatic)

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Secures the transmission fluid pan. Over-tightening can damage the pan and cause leaks. Value estimated based on industry standard for aluminum transmission pan bolts.
4

Mechatronics Unit Bolts

M5 x 0.8
Torque Value
5.9 ft-lbs (8 N·m)
Important Notes
Secures the mechatronics unit. Proper torque is critical for proper function. Value estimated based on industry standard for mechatronic units.
5

Transmission Output Shaft Flange Bolts

M10 x 1.5
Important Notes
Connects the driveshaft to the transmission output shaft. Proper torque is crucial for secure power transmission and vibration free operation. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.
6

Transmission Fill Plug

M22 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Ensures proper sealing of the fill plug. Value estimated based on similar Audi models.
7

Transmission Drain Plug

M18 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Ensures proper sealing of the drain plug. Value estimated based on similar Audi models.

Front Differential

Torque specifications for the front differential components. Ensures proper mounting, case sealing, and internal gear engagement. Critical for AWD systems.

1

Differential Mount Bolts (to Chassis)

M14 x 1.5
Important Notes
Securely mounts the front differential. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.
2

Differential Case Bolts

M10 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Clamps the differential case halves together. Over-tightening can damage the case. Value estimated based on industry standard, medium-size differential case bolt.
3

Differential Ring Gear Bolts

M12 x 1.5
Important Notes
Secures the ring gear to the differential case. Precise torque is critical for gear mesh and durability. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.
4

Differential Fill Plug

M18 x 1.5
Torque Value
26 ft-lbs (35 N·m)
Important Notes
Seals the differential fill plug to prevent fluid leakage. Value estimated based on similar Audi models.
5

Differential Drain Plug

M18 x 1.5
Torque Value
26 ft-lbs (35 N·m)
Important Notes
Seals the differential drain plug to prevent fluid leakage. Value estimated based on similar Audi models.
6

Front Driveshaft Flange Bolts (to Differential)

M10 x 1.5
Important Notes
Secures the driveshaft to the differential flange. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.

Rear Differential

Torque specifications for rear differential components, for vehicles equipped with Quattro. Ensures proper mounting, sealing and gear engagement. Critical for rear-wheel power transfer.

1

Differential Mount Bolts (to Subframe)

M14 x 1.5
Important Notes
Securely mounts the rear differential to the subframe. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.
2

Differential Case Bolts

M10 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Clamps the differential case halves together. Over-tightening can damage the case. Value estimated based on industry standard, medium-size differential case bolt.
3

Differential Ring Gear Bolts

M12 x 1.5
Important Notes
Secures the ring gear to the differential case. Precise torque is critical for gear mesh and durability. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.
4

Differential Fill Plug

M18 x 1.5
Torque Value
26 ft-lbs (35 N·m)
Important Notes
Ensures proper sealing of the fill plug. Value estimated based on similar Audi models.
5

Differential Drain Plug

M18 x 1.5
Torque Value
26 ft-lbs (35 N·m)
Important Notes
Ensures proper sealing of the drain plug. Value estimated based on similar Audi models.
6

Rear Driveshaft Flange Bolts (to Differential)

M10 x 1.5
Important Notes
Secures the driveshaft to the rear differential. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.

Driveshafts

Torque specifications for the driveshaft and axle components. Ensures proper support, secure mounting and smooth power transfer.

1

Driveshaft Center Support Bearing Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Secures the driveshaft support bearing to the chassis. Value estimated based on similar Audi models.
2

CV Axle Bolts (to wheel hub)

M10 x 1.5
Important Notes
Holds the CV axle to the wheel hub, ensuring power transfer. Torque-to-yield bolts must be replaced each time they are removed. Value estimated based on similar Audi models.

Troubleshooting Guide

Common issues, diagnostic steps, and prevention guidelines

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

1

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
2

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
3

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

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 are correct torque specifications important for drivetrain bolts?

Correct torque is crucial to ensure proper clamping force, preventing bolts from loosening due to vibration or stress. Over-torquing can stretch or damage the bolt, while under-torquing can lead to component failure, noise, and potential separation. This is especially important in the drivetrain due to high rotational forces and loads.

Q2

Can I use the same torque specs for aftermarket components?

No, generally you should not. Aftermarket components may have different material properties or thread pitch, requiring different torque specifications. Always consult the documentation provided by the aftermarket component manufacturer for their recommended torque values. Using Audi's specifications on an aftermarket component can lead to damage or failure.

Q3

What should I do if a bolt feels like it's 'stretching' while torquing?

Stop immediately. A 'stretching' sensation usually indicates the bolt is being over-torqued and is about to yield. Discard the bolt and replace it with a new one. Inspect the bolt hole for damage. Re-torque the new bolt to the correct specification using a calibrated torque wrench.

Q4

Do I need to replace bolts after they've been removed?

It is highly recommended to replace torque-to-yield (TTY) bolts, such as those used in some drivetrain applications, each time they are removed. These bolts are designed to stretch when tightened and may not achieve the correct clamping force upon reuse. Consult Audi’s repair manual or specifications to identify TTY bolts in the drivetrain.

Q5

Should I use threadlocker on drivetrain bolts?

Consult the Audi repair manual. Some drivetrain bolts are designed to be used with a specific threadlocker, while others are not. Using threadlocker where it isn't specified can alter torque values and potentially damage components. Likewise, not using it where required may cause premature loosening.

Q6

How often should I check the torque on drivetrain bolts?

Unless specifically instructed to as part of a maintenance schedule (such as after replacing components or performing a repair), it is not generally necessary to routinely check the torque on correctly installed drivetrain bolts. However, if you suspect a problem or have heard unusual noises from the area, it's advisable to check and re-torque the affected areas following the manufacturer's specifications. After making repairs, it's good practice to check again after a short test drive.

Environmental Considerations

Temperature, humidity, and seasonal effects on torque specifications

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

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

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 tightening bolts to the correct specification.

  • Accurate torque readings
  • Click-type or digital display
  • Wide torque range (e.g., 20-200 Nm)
Learn more

Torque Wrench (3/8 inch drive)

Smaller drive for access to bolts in tighter areas, also calibrated for accuracy.

  • Accurate torque readings
  • Click-type or digital display
  • Lower torque range than 1/2 inch drive (e.g., 5-80 Nm)
Learn more

Socket Set (Metric)

A complete set of metric sockets is required to fit the various bolts on the drivetrain.

  • Various sizes (e.g., 8mm - 24mm)
  • 6-point sockets for secure grip
  • Deep sockets for recessed bolts
Learn more

Universal Joint Adapter

Allows access to bolts at awkward angles.

  • Flexible joint
  • Robust construction
  • Available in different drive sizes
Learn more

Extension Bars

Provides additional reach for bolts in hard-to-access locations.

  • Various lengths
  • Available in different drive sizes
  • Solid construction
Learn more

Torx/Triple Square Bit Set

Required for specific bolts found on Audi drivetrain components.

  • Various Torx (T) sizes
  • Various Triple Square (XZN) sizes
  • Hardened steel construction
Learn more
Service Procedures

Front Axle Driveshaft Bolt Torque Procedure

Instructions for correctly torquing the bolts securing the front driveshafts to the wheel hubs.

  • Locate the specific bolts according to the workshop manual.
  • Clean the threads of the bolts and hub with a wire brush.
  • Apply a small amount of threadlocker (if specified by the manufacturer).
  • Tighten the bolts to the initial specified torque.
  • Angle tighten to the specified angle using a torque angle meter (if specified by the manufacturer).
  • Recheck torque values to ensure all bolts are correctly tightened.
View full procedure

Rear Axle Driveshaft Bolt Torque Procedure

Instructions for correctly torquing the bolts securing the rear driveshafts to the wheel hubs and differential.

  • Locate the specific bolts according to the workshop manual.
  • Clean the threads of the bolts and mating surfaces.
  • Apply a small amount of threadlocker (if specified by the manufacturer).
  • Tighten the bolts to the initial specified torque.
  • Angle tighten to the specified angle using a torque angle meter (if specified by the manufacturer).
  • Recheck torque values to ensure all bolts are correctly tightened.
View full procedure

Differential Mounting Bolt Torque Procedure

Instructions for correctly torquing the bolts securing the front and rear differential to the chassis.

  • Locate the specific bolts according to the workshop manual.
  • Clean the threads of the bolts and mating surfaces.
  • Apply a small amount of threadlocker (if specified by the manufacturer).
  • Tighten the bolts to the initial specified torque.
  • Angle tighten to the specified angle using a torque angle meter (if specified by the manufacturer).
  • Recheck torque values to ensure all bolts are correctly tightened.
View full procedure

Transmission Mounting Bolt Torque Procedure

Instructions for correctly torquing the bolts securing the transmission to the engine and chassis.

  • Locate the specific bolts according to the workshop manual.
  • Clean the threads of the bolts and mating surfaces.
  • Apply a small amount of threadlocker (if specified by the manufacturer).
  • Tighten the bolts to the initial specified torque.
  • Angle tighten to the specified angle using a torque angle meter (if specified by the manufacturer).
  • Recheck torque values to ensure all bolts are correctly tightened.
View full procedure
Technical Service Bulletins

Driveshaft Bolt Loosening Issue

2020-05-15

Some 2018-2019 S6 models may experience driveshaft bolt loosening due to improper torque application.

2018-2019 Audi S6

Resolution: Inspect driveshaft bolts. Replace bolts with revised part number and torque to updated specification using new angle torque method

Differential Mounting Bolt Failure

2021-11-22

Reports indicate differential mounting bolt failure in high-performance driving conditions. May result in damage to surrounding components.

2018-2021 Audi S6

Resolution: Inspect all differential mounting bolts. Replace bolts with revised high-strength bolt and torque to updated specification. Add additional support brackets where necessary.

Transmission Mount Bolt Inspection

2023-02-10

Issue with transmission mount bolt stretching causing excessive vibration. Some vehicles may require mount replacement

2018-2023 Audi S6

Resolution: Inspect transmission mount bolts for signs of stretching. Replace bolts with updated part number and torque to updated specification. May also require replacement of entire mount.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

ASE Master Certified Technician with over a decade of hands-on experience in automotive repair and diagnostics.

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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.
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