Audi Audi S8 1996-2011 AL450 Transmission Transmission Torque Specifications & Bolt Torque Values
Audi Audi S8 1996-2011

Audi Audi S8 1996-2011 AL450 Transmission Torque Specifications

Detailed torque specifications for all bolts related to the AL450 transmission in the 1996-2011 Audi S8. Includes transmission housing, valve body, and other related component bolt torques.

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 Housing

Torque specifications for bolts securing the main transmission case halves.

1

Transmission Case Bolts

M8 x 1.25
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Use a criss-cross pattern and tighten bolts in multiple passes to ensure even sealing and prevent warping. Estimated based on industry standards.

Valve Body

Torque specifications for bolts related to the valve body assembly.

1

Valve Body Mounting Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Tighten bolts in a criss-cross pattern to ensure even pressure. Overtightening can warp the valve body.
2

Mechatronic Unit Mounting Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Tighten bolts in a criss-cross pattern. These bolts secure the Mechatronic unit to the valve body.

Oil Pan

Torque specifications for bolts securing the transmission oil pan.

1

Oil Pan Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Tighten bolts in a criss-cross pattern to prevent leaks and distortion. Estimated value based on Audi specifications for similar components.

Transmission Mounts

Torque specifications for bolts securing the transmission mounts to the chassis and transmission.

1

Transmission Mount Bolts (Transmission to Crossmember)

M12 x 1.75
Torque Value
48 ft-lbs (65 N·m)
Important Notes
Safety-critical bolts. Ensure proper torque for stability and vibration control. Estimated based on similar Audi models.
2

Transmission Mount Bolts (Transmission to Mount Bracket)

M10 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Secures the transmission mount to the bracket on the transmission case. Estimated value based on similar Audi models.

Torque Converter

Torque specifications for bolts securing the torque converter to the engine flexplate.

1

Torque Converter Bolts (Flexplate/Drive Plate Bolts)

M10 x 1.0
Important Notes
Always replace these torque-to-yield bolts when removed. Critical bolts for transferring engine power. Use a new bolt and follow the torque sequence.

Oil Pump

Torque specifications for bolts securing the oil pump within the transmission.

1

Oil Pump Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Secures the transmission oil pump to the housing. Estimated value based on other M6 bolts in the transmission.

Speed Sensors

Torque specifications for bolts securing internal speed sensors.

1

Speed Sensor Mounting Bolts (Internal)

M5 x 0.8
Torque Value
4 ft-lbs (5.5 N·m)
Important Notes
Low torque to avoid damaging the sensitive sensors. Estimated based on similar sensor applications.

Output Shaft

Torque specifications for bolts securing the output shaft flanges to the transmission.

1

Output Shaft Flange Bolts

M10 x 1.5
Torque Value
48 ft-lbs (65 N·m)
Important Notes
Attaches the output shaft flanges (or CV joints) to the transmission. Critical for power transfer.

Cooler Lines

Torque specifications for bolts securing the transmission cooler lines.

1

Transmission Cooler Line Fittings (Bolted)

M14 x 1.5
Torque Value
30 ft-lbs (40 N·m)
Important Notes
Secures the cooler lines to the transmission case. Value is for a banjo bolt type fitting. Ensure proper torque for a leak-free seal.

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 specification so important for the AL450 transmission bolts?

Using the correct torque specification for the AL450 transmission bolts is crucial to ensure proper clamping force. Over-tightening can lead to bolt stretching, thread damage (in the aluminum transmission case), and potential component failure. Under-tightening can result in fluid leaks, vibrations, and premature wear of the transmission. Incorrect torque can also affect the precision engagement of internal components, impacting shift quality and transmission longevity. For example, improperly torqued valve body bolts can cause erratic shifting and internal fluid leaks.

Q2

What happens if I use a torque wrench that isn't calibrated?

Using an uncalibrated torque wrench can lead to inaccurate torque values, rendering the specifications useless. An over-torqued bolt may not be obvious at installation but will weaken over time, possibly leading to a failure during hard driving. Similarly, an under-torqued bolt can create a leak immediately after install or cause movement, which can break the bolt. Regular calibration of torque wrenches is essential for reliable and accurate results.

Q3

Do I need to use new bolts when working on the AL450 transmission?

While not always mandatory for all AL450 bolts, it is generally recommended to use new bolts, particularly for critical areas such as the torque converter and valve body. These bolts often undergo considerable stress, and re-using them may increase the risk of fatigue failure or stretched threads. Using new bolts ensures proper clamping force and maintains the intended design specification. Always refer to the specific repair manual for the component you are working on for the recommended bolt replacement procedure.

Q4

Are there any special tools needed for torquing AL450 transmission bolts?

Yes, you will need a torque wrench calibrated to the appropriate range for the specific bolts you are working on. Also, access to some AL450 bolts may require specialized sockets, extensions, or universal joints due to tight spaces. It's also useful to have a reference diagram to be sure that you are accessing the correct bolt. Using the wrong tool will create a safety hazard and is likely to damage the vehicle.

Q5

What is the procedure for torquing bolts in a sequence or pattern on the AL450 transmission?

When multiple bolts are used to secure a component (such as the transmission pan or valve body), it is crucial to tighten them in a specific sequence or pattern and in multiple stages. Usually, a spiral or criss-cross pattern from the center outward is used to distribute the clamping force evenly. Initially, all bolts are lightly tightened to about half the required torque, then the final torque is reached in one more (sometimes two more) sequences. Consult the service manual to view the appropriate sequence and stage torque specs. This reduces the risk of warping or uneven pressure.

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 capable of measuring torque values from 10 Nm to 150 Nm. Essential for precise bolt tightening.

  • Click-type mechanism
  • Reversible ratchet head
  • Clearly marked torque scale
Learn more

Torque Wrench (3/8-inch drive)

A calibrated torque wrench for lower torque values, typically from 5 Nm to 50 Nm, useful for smaller bolts and connections.

  • Click-type mechanism
  • Compact size
  • Fine-adjustment scale
Learn more

Socket Set (1/2-inch and 3/8-inch drive)

A comprehensive set of sockets in metric sizes, needed for accessing and tightening transmission bolts. Includes common sizes like 10mm, 13mm, 16mm, and 18mm, both standard and deep socket.

  • Metric sizes
  • Chrome vanadium steel construction
  • 6-point and 12-point options
Learn more

Extension Bars (various lengths)

Extension bars of various lengths to reach recessed bolts and provide extra clearance when tightening.

  • Multiple lengths
  • Secure connection to sockets
  • Durable construction
Learn more

Universal Joint

Allows the socket to be angled when access is difficult, ensuring proper alignment when tightening bolts in tight areas.

  • Flexible joint
  • Secure locking mechanism
  • Chrome finish
Learn more

Thread Locker (Medium Strength)

A medium strength thread locking compound to secure bolts and prevent loosening under vibration and heat.

  • Resistant to oil and chemicals
  • Medium hold strength
  • Easy to remove if necessary
Learn more
Service Procedures

AL450 Transmission Oil Pan Removal and Installation

Procedure for safely removing and reinstalling the transmission oil pan and ensuring proper sealing and bolt torque specifications. Crucial for fluid changes and maintenance.

  • Drain transmission fluid from pan.
  • Remove all oil pan bolts.
  • Carefully pry the oil pan from the transmission housing.
  • Clean the oil pan and transmission housing mating surfaces.
  • Install new oil pan gasket or sealant.
  • Reinstall the oil pan and loosely install all bolts.
  • Tighten the oil pan bolts in a criss-cross pattern to the specified torque (approximately 20-25 Nm).
  • Refill transmission fluid to proper level.
View full procedure

AL450 Transmission Valve Body Bolt Torque

Procedure to correctly remove and tighten valve body bolts to prevent leaks and maintain transmission performance. Precise torque is essential to prevent distortion or damage to the valve body.

  • Remove the transmission oil pan.
  • Disconnect all electrical connectors on the valve body.
  • Carefully remove the valve body from the transmission housing.
  • Clean valve body and mating surfaces on the transmission housing.
  • Install the valve body and loosely install the mounting bolts.
  • Tighten valve body bolts to the specified torque (approximately 10-12 Nm) in a criss-cross pattern.
  • Reconnect all electrical connectors.
  • Reinstall the transmission oil pan.
  • Refill transmission fluid to proper level.
View full procedure

AL450 Torque Converter Bolt Torque

Procedure for removing and reinstalling torque converter bolts ensuring proper alignment, correct bolt torque, and preventing vibration or damage to the flywheel.

  • Access torque converter bolts through the inspection hole.
  • Rotate the engine to access each bolt.
  • Remove torque converter bolts.
  • Align torque converter to the flywheel.
  • Install all the bolts loosely.
  • Tighten torque converter bolts to the specified torque (approximately 40-50 Nm) in a criss-cross pattern. Use thread locker.
  • Verify correct torque.
View full procedure
Technical Service Bulletins

AL450 Transmission Oil Pan Gasket Leakage

2005-07-15

Bulletin detailing issues with the original oil pan gasket leading to leaks. Recommends the use of an improved gasket design or sealant.

1996-2004 Audi S8 with AL450 transmission

Resolution: Use of an updated gasket or application of sealant on the oil pan mating surfaces in conjunction with correct torque of 20-25 Nm.

AL450 Valve Body Bolt Loosening

2008-02-29

Technical bulletin addressing the potential for valve body bolts to loosen over time and mileage, potentially leading to erratic transmission behavior. Recommends torque check and use of thread locker.

1996-2008 Audi S8 with AL450 transmission

Resolution: Inspect valve body bolts and ensure proper torque. Re-torque to 10-12 Nm with medium-strength thread locker applied to each bolt.

AL450 Torque Converter Bolt Stretch

2010-11-10

Bulletin addressing the potential for torque converter bolts to stretch under heavy load. Recommends single-use bolts and correct torque procedure to prevent flywheel damage.

1996-2011 Audi S8 with AL450 transmission

Resolution: Always replace torque converter bolts. Install new bolts and tighten them to 40-50 Nm using medium strength thread locker in a cross pattern.

About the Author

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Alan Montanye - Automotive Technical Specialist
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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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