Audi Audi S4 2009-2016 DL501 Transmission Transmission Torque Specifications & Bolt Torque Values
Audi Audi S4 2009-2016

Audi Audi S4 2009-2016 DL501 Transmission Torque Specifications

Detailed torque specifications for all bolts related to the DL501 transmission found in the 2009-2016 Audi S4 B8 platform.

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

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Transmission Housing

These specifications cover bolts related to the main transmission case, bellhousing, and external attachments.

1

Transmission Housing Bolts (Main Case)

M10 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Tighten evenly in a crisscross pattern. Estimated value based on similar applications.
2

Bellhousing Bolts (to Engine)

M12 x 1.75
Torque Value
45 ft-lbs (60 N·m)
Important Notes
Tighten in a star pattern to ensure even clamping force. Estimated value based on similar applications. These are safety critical.
3

Transmission Support Bracket Bolts (to Chassis)

M12 x 1.75
Torque Value
40 ft-lbs (55 N·m)
Important Notes
Estimated value based on similar applications.
4

Mechatronic Unit Bolts (to transmission case)

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Tighten evenly in a crisscross pattern due to the delicate nature of the mechatronic unit. Estimated value, check service manual if possible.
5

Oil Pan Bolts (Transmission)

M6 x 1.0
Torque Value
7 ft-lbs (10 N·m)
Important Notes
Tighten evenly in a crisscross pattern. Be careful not to over-tighten, as this can damage the pan or gasket. Estimated value based on similar applications.
6

Transmission Fluid Drain Plug

M18 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Ensure the sealing washer is in good condition and replace if necessary. Estimated value based on similar applications.
7

Transmission Fluid Fill Plug

M18 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Ensure the sealing washer is in good condition and replace if necessary. Estimated value based on similar applications.

Internal Components

These specifications pertain to bolts securing internal transmission components.

1

Clutch Pack Retainer Bolts

M8 x 1.25
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Ensure even clamping of the clutch assembly. These bolts may need to be replaced upon disassembly. Estimated value based on similar applications.
2

Control Piston Bolts (Internal)

M6 x 1.0
Torque Value
12 ft-lbs (16 N·m)
Important Notes
Tighten in a star pattern to ensure even pressure on the piston. Estimated value based on similar applications.
3

Internal Sensor Mounting Bolts

M5 x 0.8
Torque Value
6 ft-lbs (8 N·m)
Important Notes
These bolts secure sensors. Low torque value due to the sensitivity of sensor components. Estimated value based on similar applications.
4

Differential Housing Bolts (Internal)

M10 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Ensure even and proper alignment of the differential. Estimated value based on similar applications.
5

Parking Pawl Bolt (Retaining)

M8 x 1.25
Torque Value
10 ft-lbs (14 N·m)
Important Notes
Critical for proper parking function. Estimated value based on similar applications.
6

Output Shaft Flange Bolt

M12 x 1.5
Important Notes
This is a high torque stretch bolt. Replace anytime it is removed. Ensure correct tightening procedure. Estimated value based on similar applications. This is safety critical.

External Components

Specifications for external components attached to the transmission.

1

Coolant Line Fittings (to transmission)

M10 x 1.0 (banjo bolt)
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Do not overtighten, as this can cause leaks. Ensure banjo washers are in good condition. Estimated value based on similar applications.
2

Electrical Connector Retaining Bolt

M5 x 0.8
Torque Value
4 ft-lbs (5 N·m)
Important Notes
Low torque value due to the plastic housing of the connector. Estimated value based on similar applications.

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 is using the correct torque specifications important for DL501 transmission bolts?

Using the correct torque specifications is crucial to ensure a proper and secure connection of transmission components. Under-torquing can lead to bolts loosening during operation, causing leaks, damage to the transmission, or even complete failure. Over-torquing can stretch or break bolts, damage threads in the transmission case, or distort mating surfaces, also resulting in component failure. Accurate torque ensures even clamping force and proper sealing.

Q2

What happens if I reuse bolts, especially torque-to-yield bolts, in the DL501 transmission?

Reusing torque-to-yield (TTY) bolts is strongly discouraged. These bolts are designed to stretch a specific amount during tightening and should not be used again after being tightened. Reusing them may lead to improper clamping, loosening, or failure. TTY bolts should ALWAYS be replaced with new ones for each removal and installation. Always consult the manufacturer's specifications to identify the TTY bolts present in the transmission system.

Q3

Should I apply threadlocker to DL501 transmission bolts?

Whether or not to use threadlocker depends on the specific bolt location and the manufacturer's recommendations. In general, threadlocker may be required on bolts that are not self-locking or in areas prone to vibration. Always refer to the specific workshop manual for your vehicle model. Using the wrong threadlocker or applying it when it is not needed can make future servicing more difficult and even introduce unintended complications.

Q4

What type of tool is recommended for tightening DL501 transmission bolts?

A calibrated torque wrench is essential for tightening DL501 transmission bolts to their correct specifications. Using an impact wrench or tightening bolts by 'feel' is highly inaccurate and can result in under or over-tightening. A torque wrench with a range that covers the required torque values and is regularly calibrated will ensure proper tightening. Consider using a torque angle gauge when tightening fasteners with a specific torque-angle procedure.

Q5

Can I visually inspect bolts to tell if they are torqued correctly?

No, visual inspection is insufficient to determine if a bolt is torqued correctly. Over or under-tightening can be very hard to detect visually. Always use a calibrated torque wrench and follow the specified torque values and tightening sequence. For instance, a bolt may appear tightened but could be under-torqued and prone to failure over time.

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" Drive)

A calibrated torque wrench is essential for applying accurate torque to transmission bolts, preventing damage and ensuring proper assembly.

  • 1/2" Drive for common bolt sizes
  • Wide torque range (typically 20-200 Nm)
  • Click-type or digital readout for precise measurement
Learn more

Torque Wrench (3/8" Drive)

A smaller torque wrench for lower torque fasteners found on the transmission.

  • 3/8" Drive for smaller bolts
  • Lower torque range (typically 5-50 Nm)
  • Click-type or digital readout for precise measurement
Learn more

Socket Set (Metric)

A comprehensive set of metric sockets to fit all the different sized bolts on the DL501 transmission.

  • 10mm - 19mm sizes
  • Standard depth and deep sockets
  • 6-point design for secure grip
Learn more

Extension Bars (1/2" and 3/8")

Extension bars to reach recessed or difficult to access bolts on the transmission.

  • Various lengths for access
  • Durable steel construction
  • Available in 1/2" and 3/8" drive sizes
Learn more

Universal Joint (1/2" and 3/8")

Allows socket access at an angle when direct access is not possible.

  • Provides flexible socket articulation
  • Durable steel construction
  • Available in 1/2" and 3/8" drive sizes
Learn more
Service Procedures

Mechatronic Unit Bolt Torque Procedure

This procedure outlines the tightening sequence and torque specification for the bolts securing the mechatronic unit to the DL501 transmission.

  • Locate all mechatronic unit bolts.
  • Begin tightening the bolts in a criss-cross pattern, incrementally increasing torque.
  • First pass, tighten all bolts to 8 Nm.
  • Second pass, tighten all bolts to 20 Nm.
  • Check torque on all bolts to ensure correct specification is met.
View full procedure

Transmission Pan Bolt Torque Procedure

This procedure details the proper method for tightening the bolts that secure the transmission pan to the DL501 transmission.

  • Locate all transmission pan bolts.
  • Begin tightening the bolts in a criss-cross pattern, incrementally increasing torque.
  • Tighten all bolts to 15 Nm.
  • Check torque on all bolts to ensure correct specification is met.
View full procedure

Transmission Mount Bolt Torque Procedure

This procedure covers the tightening process for bolts securing the transmission mount to the chassis and transmission housing.

  • Locate all transmission mount bolts.
  • First pass, tighten all transmission mount bolts to 20 Nm.
  • Second pass, tighten all transmission mount bolts to 40 Nm + 90°.
  • Check torque and angle to ensure proper specifications are met.
View full procedure

Differential Bolt Torque Procedure

This procedure details how to properly torque the bolts connecting the differential to the DL501 transmission.

  • Locate all differential housing bolts.
  • First pass, tighten all differential bolts to 30 Nm.
  • Second pass, tighten all bolts to 50 Nm.
  • Check torque on all bolts to ensure correct specification is met.
View full procedure
Technical Service Bulletins

DL501 Mechatronic Unit Bolt Loosening

2014-05-15

Some reported cases of mechatronic unit bolts loosening on vehicles. This can lead to transmission fluid leaks and potential damage.

2009-2012 Audi S4

Resolution: Inspect mechatronic unit bolts regularly. Follow the correct tightening sequence and torque to 20 Nm, replace bolts if previously loosened, and ensure proper fluid level.

Transmission Pan Bolt Leakage

2015-11-20

Reports of transmission pan leaks due to improper installation and torque application. Ensure bolts are replaced and tightened to the specified torque to prevent leaks.

2010-2016 Audi S4

Resolution: Replace pan bolts with new bolts during any service procedure involving removal of the pan. Tighten to specified 15 Nm torque using a criss-cross pattern. Use a new pan gasket for best results.

About the Author

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Alan Montanye - Automotive Technical Specialist
ASE

Alan Montanye

Automotive Technical Specialist

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