BMW 640i 2011-2018 Drivetrain Bolt Torque Specifications & Fastener Values
BMW 640i 2011-2018

BMW 640i 2011-2018 Drivetrain Bolt Torque Specifications

This page provides detailed torque specifications for various bolts within the drivetrain system of the 2011-2018 BMW 640i (F12/F13) generation, 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

Engine Flywheel

Components related to the connection between the engine crankshaft and the transmission. Includes both manual transmission flywheels and automatic transmission flexplates.

1

Flywheel to Crankshaft Bolts

M12 x 1.25
Torque Value
60 ft-lbs (81 N·m)
Important Notes
Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer.
2

Flex Plate to Crankshaft Bolts

M12 x 1.25
Important Notes
Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer. Final torque is achieved through a combination of torque and angle tightening.
3

Torque Converter to Flex Plate Bolts

M10 x 1.25
Torque Value
30 ft-lbs (41 N·m)
Important Notes
Ensure mating surfaces are clean and that the torque converter is properly seated to the flexplate. Verify the correct bolt length is used, excessively long bolts can cause damage.

Transmission Mounting

Bolts associated with mounting the transmission assembly to the engine and/or chassis.

1

Transmission Mounting Bolts

M12 x 1.75
Torque Value
35 ft-lbs (47 N·m)
Important Notes
Ensure proper alignment of transmission before tightening. Use new bolts if recommended by manufacturer.

Transmission Service

Bolts related to servicing the transmission, including the oil pan and fill/drain plugs.

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Value
15 ft-lbs (20 N·m)
Important Notes
Tighten in a criss-cross pattern to avoid warping the pan. Always use a new gasket for proper sealing.
2

Transmission Drain and Fill Plugs

M22 x 1.5
Torque Value
20 ft-lbs (27 N·m)
Important Notes
Use a new sealing washer or O-ring to ensure a proper seal.

Drive Axles

Components and fasteners associated with the drive axles, half shafts, and CV (Constant Velocity) joints.

1

Drive Axle/Half Shaft Bolts

M10 x 1.5
Torque Value
80 ft-lbs (108 N·m)
Important Notes
Ensure the drive axle is properly seated before tightening.
2

CV Joint/Axle Nut

M24 x 1.5
Torque Value
210 ft-lbs (285 N·m)
Important Notes
This nut often requires a very high torque and should be torqued with the vehicle's wheels on the ground. Always replace the nut with a new one.
3

Drive Axle to Differential Flange Bolts

M10 x 1.5
Torque Value
60 ft-lbs (81 N·m)
Important Notes
Estimated value based on similar bolt sizes. Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer.

Driveshaft

Components related to the drive shaft (also known as propeller shaft) which transmits power from the transmission to the differential.

1

Propeller/Drive Shaft Bolts

M10 x 1.5
Torque Value
70 ft-lbs (95 N·m)
Important Notes
Ensure proper alignment of the drive shaft before tightening. Use new bolts if recommended by manufacturer. Some applications may use a self locking nut, and those should always be replaced.
2

Transmission Output Shaft Flange Bolts

M10 x 1.5
Torque Value
45 ft-lbs (61 N·m)
Important Notes
Estimated value based on similar bolt sizes. Ensure mating surfaces are clean. Apply a thin layer of anti-seize compound to bolt threads if specified by the manufacturer.

Differential

Components related to the differential assembly, which distributes power to the wheels.

1

Differential Drain/Fill Plug

M20 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer or O-ring to ensure a proper seal.
2

Differential Mounting Bolts

M14 x 2.0
Torque Value
60 ft-lbs (81 N·m)
Important Notes
Estimated value based on similar bolt sizes. Ensure proper alignment of differential before tightening. Use new bolts if recommended by manufacturer.

Transfer Case

Components related to the transfer case, found in all-wheel-drive (AWD) and four-wheel-drive (4WD) vehicles.

1

Transfer Case Drain/Fill Plug

M20 x 1.5
Torque Value
25 ft-lbs (34 N·m)
Important Notes
Use a new sealing washer or O-ring to ensure a proper 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 are torque specifications important for drivetrain bolts?

Proper torque ensures bolts are neither too loose, which can lead to component failure or separation, nor too tight, which can cause bolt stretching, damage, or thread stripping. Using a torque wrench to achieve the specified torque value is crucial for the safe and reliable operation of the drivetrain. For example, under-torqued differential bolts can cause excessive movement and premature wear, while over-torqued bolts may crack the housing.

Q2

What happens if I don't use a torque wrench?

Without a torque wrench, you risk either under-tightening or over-tightening bolts. 'Feeling' the torque is not reliable, as individual force perception varies. Under-tightening can lead to parts loosening, vibration, and potential component failure. Over-tightening can damage threads, break bolts, or distort the components being bolted together. For example, a wheel bearing hub can be severely damaged by over-torquing the securing bolts.

Q3

Do I need to replace drivetrain bolts after removing them?

It depends. Some bolts are designed for single use and should always be replaced. These are often called 'torque-to-yield' bolts and are designed to stretch upon tightening, providing a precise clamping force. Reusing these can lead to incorrect clamping pressure. While some bolts may be reused, it's always best practice to consult the BMW repair manual for your specific model. For instance, driveshaft bolts often require replacement after removal.

Q4

Should I use thread locker on drivetrain bolts?

Yes, in some cases, thread locker is recommended, especially on bolts that are subject to vibration and stress, such as those on the transmission output flange or driveshaft joints. The specific type (e.g., Loctite 242 - blue) is often specified in the repair manual. Proper cleaning of threads before applying thread locker is also crucial. Always refer to the repair manual for guidance on which bolts require thread locker.

Q5

What are common symptoms of improperly torqued drivetrain bolts?

Symptoms can include unusual noises (clunking, grinding), vibrations, play in the drivetrain components, fluid leaks, or complete failure. For example, loose differential mounting bolts may cause a loud clunk when accelerating or decelerating, while loose driveshaft bolts may manifest as a vibration at certain speeds. If you notice any of these, immediately inspect the drivetrain components.

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 within the range specified for BMW drivetrain components. 1/2-inch drive is suitable for most drivetrain bolts.

  • Click-type mechanism for accurate torque application
  • Wide torque range (e.g., 20-150 ft-lbs or similar in Nm)
  • Ratchet mechanism for easy tightening
Learn more

Torque Wrench (3/8-inch Drive)

A smaller torque wrench for lower torque applications on smaller drivetrain components.

  • Click-type mechanism for accurate torque application
  • Lower torque range (e.g., 5-80 ft-lbs or similar in Nm)
  • Ratchet mechanism for easy tightening
Learn more

Socket Set (Metric)

A comprehensive set of metric sockets, including standard and deep sockets, to accommodate the various bolt head sizes found in the BMW drivetrain.

  • Sizes ranging from 8mm to 24mm (or larger)
  • 6-point design for secure bolt grip
  • Durable construction for repeated use
Learn more

Extension Bars

Various length extensions for torque wrench to reach bolts in recessed areas

  • Multiple lengths
  • Durable construction
Learn more

Universal Joint

Allows torque wrench application at angles

  • Durable construction
  • Fits 1/2 and 3/8 drive wrenches
Learn more
Service Procedures

Driveshaft Bolt Torque Procedure

Procedure for tightening the bolts connecting the driveshaft to the transmission and differential. Incorrect torque can lead to vibrations or damage.

  • 1. Refer to the BMW TIS (Technical Information System) or repair manual for specific torque specifications for the 2011-2018 BMW 640i.
  • 2. Clean the bolt threads and mating surfaces.
  • 3. Install the driveshaft bolts by hand initially.
  • 4. Using the appropriate torque wrench and socket, torque the bolts to the specified value in a star pattern to evenly distribute clamping force.
  • 5. Double-check each bolt with the torque wrench to ensure proper tightness.
View full procedure

Differential Mounting Bolt Torque Procedure

Procedure for tightening the bolts that secure the differential to the subframe. Incorrect torque can lead to vibrations, noise, or premature wear of bushings.

  • 1. Refer to the BMW TIS (Technical Information System) or repair manual for specific torque specifications for the 2011-2018 BMW 640i.
  • 2. Clean the bolt threads and mating surfaces.
  • 3. Install the differential bolts by hand initially.
  • 4. Using the appropriate torque wrench and socket, torque the bolts to the specified value in a star pattern to evenly distribute clamping force.
  • 5. Double-check each bolt with the torque wrench to ensure proper tightness.
View full procedure

Transmission Mount Bolt Torque Procedure

Procedure for tightening the bolts that secure the transmission to the chassis. Incorrect torque can lead to vibrations, noise, or premature wear of bushings.

  • 1. Refer to the BMW TIS (Technical Information System) or repair manual for specific torque specifications for the 2011-2018 BMW 640i.
  • 2. Clean the bolt threads and mating surfaces.
  • 3. Install the transmission mount bolts by hand initially.
  • 4. Using the appropriate torque wrench and socket, torque the bolts to the specified value in a star pattern to evenly distribute clamping force.
  • 5. Double-check each bolt with the torque wrench to ensure proper tightness.
View full procedure
Technical Service Bulletins

Vibration Issues Related to Driveshaft Bolts

2017-03-15

Some 2011-2017 BMW 640i models may experience driveline vibrations if the driveshaft bolts are not torqued to the proper specification or if the bolts are reused. Always use new bolts when reinstalling.

2011-2017

Resolution: Replace the driveshaft bolts with new ones, and torque to the specified values outlined in the TIS. Ensure proper bolt thread cleaning and mating surface inspection prior to installation. Check driveshaft for any imbalance.

Differential Noise Related to Incorrect Mounting Torque

2015-11-01

Reports of noise from the differential area have been linked to incorrect torque on the differential mounting bolts on 2011-2015 BMW 640i models.

2011-2015

Resolution: Verify the correct torque values for the differential mounting bolts using BMW TIS. Loosen all bolts, inspect for damage or wear, and then torque to specification using a calibrated torque wrench. Ensure proper bolt thread cleaning and mating surface inspection prior to installation.

Premature Bushing Wear due to Improper Transmission Mount Torque

2014-06-20

Premature wear of transmission mounts can occur if mount bolts are improperly torqued. Symptoms include vibrations and excessive drivetrain movement.

2011-2014

Resolution: Inspect transmission mounts for damage or wear. If mounts are in good condition or have been replaced, ensure correct torque of the mount bolts according to TIS specifications. Ensure proper bolt thread cleaning and mating surface inspection prior to installation.

About the Author

Expert automotive knowledge and experience

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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