Audi Audi A5 2007-2016 AL551 Transmission Torque Specifications
Detailed torque specifications for all bolts on the AL551 automatic transmission used in the 2007-2016 Audi A5. Includes housing, valve body, and other relevant bolt torques.
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
Al551-transmission Housing
Torque specifications for the transmission housing and mounting components.
1 Transmission Mounting Bolts
M12 x 1.75
Transmission Mounting Bolts
M12 x 1.75Torque Value
Important Notes
2 Transmission Oil Pan Bolts
M6 x 1.0
Transmission Oil Pan Bolts
M6 x 1.0Torque Value
Important Notes
3 Transmission Fluid Drain Plug
M18 x 1.5
Transmission Fluid Drain Plug
M18 x 1.5Torque Value
Important Notes
4 Transmission Fluid Fill Plug
M18 x 1.5
Transmission Fluid Fill Plug
M18 x 1.5Torque Value
Important Notes
5 Transmission Output Flange Bolt
M10 x 1.25
Transmission Output Flange Bolt
M10 x 1.25Torque Value
Important Notes
Al551-mechatronic Unit
Torque specifications for the mechatronic unit and related components.
1 Mechatronic Unit Mounting Bolts
M6 x 1.0
Mechatronic Unit Mounting Bolts
M6 x 1.0Torque Value
Important Notes
2 Transmission Valve Body Mounting Bolts
M6 x 1.0
Transmission Valve Body Mounting Bolts
M6 x 1.0Torque Value
Important Notes
Al551-driveline
Torque specifications for driveline components connected to the transmission.
1 Drive Axle/Half Shaft Bolts
M10 x 1.25
Drive Axle/Half Shaft Bolts
M10 x 1.25Torque Value
Important Notes
2 Torque Converter Bolts
M10 x 1.25
Torque Converter Bolts
M10 x 1.25Important Notes
Al551-cooling
Torque specifications for the transmission cooler lines and related components.
1 Transmission Cooler Line Banjo Bolts
M14 x 1.5
Transmission Cooler Line Banjo Bolts
M14 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 What happens if I overtighten the transmission bolts?
What happens if I overtighten the transmission bolts?
Overtightening can stretch or shear the bolts, damage the transmission case threads, and potentially lead to leaks, component failure, or separation of components. It can create a weakened point. For instance, if an overtightened bolt on the oil pan begins to leak, it may require a costly transmission disassembly to replace the case.
Q2 Can I reuse the transmission bolts?
Can I reuse the transmission bolts?
Generally, it is recommended to replace the transmission bolts, especially those that are torque-to-yield (TTY) bolts, which are designed to stretch upon installation. Reusing them can lead to improper clamping force and potential failure. For instance, many of the valve body bolts are TTY. Reusing them could lead to leaks, or damage to the valve body or transmission case. Even if they are not torque-to-yield, the bolts may be fatigued. Therefore, always refer to the Audi service manual recommendations.
Q3 How do I properly use a torque wrench?
How do I properly use a torque wrench?
Ensure your torque wrench is calibrated and set to the correct specification. Apply smooth, even pressure until the wrench clicks, indicating the specified torque has been reached. Avoid jerking or overshooting the torque setting. For example, if a bolt calls for 25 Nm, set your torque wrench to 25Nm and tighten slowly until the wrench clicks. Do not continue tightening after the click.
Q4 Are there different torque specifications for different transmission bolts?
Are there different torque specifications for different transmission bolts?
Yes, absolutely. Torque specifications vary based on the bolt size, material, and location within the transmission. For example, the bolts holding the valve body will have a very different torque value than those connecting the transmission housing to the engine. Always refer to the specific service manual for your particular application.
Q5 Do I need to use thread locker on the transmission bolts?
Do I need to use thread locker on the transmission bolts?
Thread locker usage depends on the specific bolt location and application, as outlined in the Audi service manual. Some bolts, especially those that might be exposed to vibration or heat, require thread locker to prevent loosening. Always follow the Audi service manual recommendations and use the specified type, such as Loctite 243.
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" Drive)
A calibrated torque wrench capable of measuring torque values within the specified range for transmission bolts.
- Accurate torque measurement
- Click-type mechanism for precise application
Socket Set (Metric)
A set of metric sockets, specifically including sizes needed for transmission bolts (typically 13mm, 16mm, 18mm).
- Durable construction
- Comprehensive size range
Extension Bars (1/2" Drive)
Extension bars of various lengths to access recessed transmission bolts.
- Provides extended reach
- Durable construction
Universal Joint (1/2" Drive)
A universal joint to allow torque application at an angle when necessary.
- Allows flexible torque application
- Durable construction
Service Procedures
AL551 Transmission Mount Bolt Torque Procedure
Procedure for tightening the bolts securing the transmission mount to the chassis and transmission.
- Locate all transmission mount bolts.
- Using a torque wrench and appropriate socket, tighten the mount bolts to 40 Nm + 90 degrees.
- Verify torque application with a final check.
AL551 Transmission Pan Bolt Torque Procedure
Procedure for tightening the bolts securing the transmission oil pan.
- Locate all transmission pan bolts.
- Tighten all pan bolts in a cross pattern to 8 Nm.
- Verify torque application with a final check.
AL551 Mechatronics Unit Bolt Torque Procedure
Procedure for tightening the bolts securing the Mechatronics unit to the transmission housing.
- Locate all Mechatronics unit bolts.
- Tighten all bolts in a cross pattern to 8 Nm.
- Verify torque application with a final check.
Technical Service Bulletins
AL551 Transmission Mount Bolt Loosening Issue
2011-05-15Some instances of transmission mount bolt loosening have been reported, leading to excessive vibration. Inspection and re-torqueing are recommended.
Resolution: Inspect transmission mount bolts for proper torque. Apply 40 Nm + 90 degrees if necessary.
AL551 Transmission Oil Pan Leakage Concerns
2014-09-20Reports of transmission fluid leaks from the oil pan have been attributed to improper torqueing or reuse of old bolts. Recommended to use a new pan and new bolts
Resolution: Ensure proper tightening sequence and torque spec of 8 Nm when replacing the oil pan or the oil pan gasket. Replace pan bolts.
AL551 Mechatronics Unit Bolt Concerns
2010-02-28Improper torque application on the Mechatronics unit bolts can lead to electronic faults. Use new bolts.
Resolution: Ensure proper torque of 8 Nm using a calibrated torque wrench. Always use new bolts.
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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.