BMW 440i 2017-present Drivetrain Bolt Torque Specifications
Detailed torque specifications for all drivetrain bolts on the 2017-Present BMW 440i (F32, F33, F36) including transmission, driveshaft, differential, and axle bolts.
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
Engine To Transmission
Specifications for bolts connecting the engine to the transmission, including the flywheel (manual) or flex plate (automatic), and the transmission mounting.
1 Flywheel Bolts
M12 x 1.5
Flywheel Bolts
M12 x 1.5Torque Value
Important Notes
2 Flex Plate Bolts (Automatic Transmission)
M10 x 1.25
Flex Plate Bolts (Automatic Transmission)
M10 x 1.25Important Notes
3 Transmission Mounting Bolts
M12 x 1.75
Transmission Mounting Bolts
M12 x 1.75Torque Value
Important Notes
Transmission
Specifications for bolts related to the transmission housing, oil pan, and fluid plugs.
1 Transmission Oil Pan Bolts
M6 x 1.0
Transmission Oil Pan Bolts
M6 x 1.0Torque Value
Important Notes
2 Transmission Drain Plug
M18 x 1.5
Transmission Drain Plug
M18 x 1.5Torque Value
Important Notes
3 Transmission Fill Plug
M18 x 1.5
Transmission Fill Plug
M18 x 1.5Torque Value
Important Notes
Driveshaft
Specifications for bolts connecting the driveshaft to the transmission and differential, as well as the center support bearing.
1 Propeller/Drive Shaft Bolts
M10 x 1.5
Propeller/Drive Shaft Bolts
M10 x 1.5Torque 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
Differential
Specifications for bolts related to the differential housing, mounting, and fluid plugs.
1 Differential Mounting Bolts/Nuts
M14 x 2.0
Differential Mounting Bolts/Nuts
M14 x 2.0Torque Value
Important Notes
2 Differential Drain Plug
M16 x 1.5
Differential Drain Plug
M16 x 1.5Torque Value
Important Notes
3 Differential Fill Plug
M16 x 1.5
Differential Fill Plug
M16 x 1.5Torque Value
Important Notes
Axles
Specifications for bolts securing the drive axles and CV joints to the transmission and wheel hubs.
1 Drive Axle/Half Shaft Bolts
M10 x 1.25
Drive Axle/Half Shaft Bolts
M10 x 1.25Torque Value
Important Notes
2 CV Joint/Axle Nut
M24 x 1.5
CV Joint/Axle Nut
M24 x 1.5Torque Value
Important Notes
Transfer Case
Specifications for bolts related to the transfer case housing, mounting, and fluid plugs. Note: not all BMW 440i models will have a transfer case.
1 Transfer Case Drain Plug
M16 x 1.5
Transfer Case Drain Plug
M16 x 1.5Torque Value
Important Notes
2 Transfer Case Fill Plug
M16 x 1.5
Transfer Case Fill Plug
M16 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 are torque specifications important for drivetrain bolts?
Why are torque specifications important for drivetrain bolts?
Correct torque is crucial for drivetrain bolt integrity. Under-tightening can lead to loosening and component failure, while over-tightening can cause bolt stretching, thread damage, or component cracking. Both can result in drivetrain malfunction and potential safety hazards. For example, improper torque on the driveshaft bolts can cause vibration and even detachment at high speeds.
Q2 What happens if I don't use a torque wrench?
What happens if I don't use a torque wrench?
Without a torque wrench, it's nearly impossible to apply the correct torque consistently. Relying on 'feel' is unreliable and often leads to either under- or over-tightening. This can create a risk of failure, especially in a high-stress area like the drivetrain. A common example is damaging the threads when tightening the differential cover bolts by hand.
Q3 Can I reuse drivetrain bolts?
Can I reuse drivetrain bolts?
Generally, it's recommended to replace torque-to-yield bolts, which are often used in drivetrain components (like the driveshaft or CV joints) as they permanently stretch when torqued. These bolts should never be reused. Reusing these bolts can lead to component failure even with accurate torque. Refer to BMW service manuals for specific bolt replacement guidance.
Q4 What should I do if a bolt feels like it's stripping?
What should I do if a bolt feels like it's stripping?
If a bolt starts to feel like it's stripping, stop immediately. Continued tightening will worsen the situation. First, inspect the threads. If they are damaged, you will need to repair them with a thread repair tool, or replace the bolt and possibly the receiving part. Never force a bolt - it is better to fix it correctly. Trying to force it may cause cross-threading and additional part damage.
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 fasteners to the specified torque values. A 1/2 inch drive is recommended for most drivetrain components.
- Wide torque range (typically 20-250 ft-lbs)
- Audible click indicating achieved torque
- Ratchet mechanism for ease of use
Torque Wrench (3/8 inch Drive)
A smaller torque wrench, like a 3/8 inch drive, is helpful for some smaller fasteners or areas that are difficult to reach with the larger 1/2 inch drive wrench.
- Smaller torque range (typically 5-80 ft-lbs)
- Audible click indicating achieved torque
- Ratchet mechanism for ease of use
Socket Set (Metric)
A comprehensive set of metric sockets is necessary to fit all the various bolt and nut sizes found on the drivetrain.
- Wide range of socket sizes (8mm-24mm)
- Deep and standard socket options
- 6-point or 12-point socket options
Torque Angle Gauge
Required for fasteners that require an angle torque after the initial torque specification is reached.
- Ability to measure degrees
- Magnetic base
Universal Joint Socket Adapter
Used to access fasteners at angles.
- Allows sockets to pivot at an angle
- Provides better access in tight spaces
Extension Bars
Helpful to reach fasteners in recessed areas or in difficult to access spots.
- Available in various lengths
- Allows access to hard-to-reach fasteners
Service Procedures
Driveshaft Bolt Torque Procedure
This procedure outlines the process for correctly torquing the driveshaft bolts on a 2017-Present BMW 440i.
- Loosely install all driveshaft bolts.
- Using the appropriate socket, torque all bolts in a star pattern to the initial specified torque.
- Using a torque angle gauge apply the required angle to the specified bolts in a star pattern.
Differential Mounting Bolt Torque Procedure
This procedure describes the proper steps for tightening the differential mounting bolts to ensure secure and correct installation.
- Loosely install all differential mounting bolts.
- Using the appropriate socket, torque all bolts to the initial torque spec in a star pattern.
- Using a torque angle gauge apply the required angle to the specified bolts in a star pattern.
Axle Shaft Nut Torque Procedure
This procedure describes how to properly tighten axle nuts.
- Loosely install the axle nut.
- Using the appropriate socket torque the nut to the specified torque.
- Double check the torque.
Technical Service Bulletins
Driveshaft Bolt Corrosion Concerns
2020-05-15Some 2017-2019 BMW 440i models have reported driveshaft bolt corrosion. This can lead to improper torque and eventual failure.
Resolution: Inspect all driveshaft bolts for corrosion. Replace corroded bolts with new, properly coated bolts. Adhere to the proper torque specifications outlined in the service manual.
Differential Mount Bushing Wear
2021-11-01Reports of excessive wear on the differential mount bushings have been reported. This can cause clunking noises, and improper torque on the differential.
Resolution: Inspect the differential mount bushings for wear or damage. If worn, replace the bushings with new ones before torquing the differential bolts to the specification.
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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.