Lexus GS 2012-2020 U660E Transmission Transmission Torque Specifications & Bolt Torque Values
Lexus GS 2012-2020

Lexus GS 2012-2020 U660E Transmission Torque Specifications

Detailed torque specifications for the U660E transmission bolts in the 2012-2020 Lexus GS. Includes bolt types, torque values, and installation tips.

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 mounting

Secures the transmission to the engine block or transmission crossmember, ensuring proper alignment and preventing movement or vibration that could affect transmission performance.

1

Transmission Mounting Bolts

M14 x 1.5
Torque Value
44 ft-lbs (60 N·m)

Transmission oil pan

Secures the oil pan to the transmission case, preventing oil leaks and ensuring proper lubrication of the transmission components.

1

Transmission Oil Pan Bolts

M10 x 1.25
Torque Value
71 in-lbs (8 N·m)
Important Notes
Note: The torque value is specified in inch-pounds (in-lbs) instead of foot-pounds (ft-lbs).

Transmission fluid system

Allows for the draining and filling of transmission fluid, and proper torque ensures a leak-free seal.

1

Transmission Drain and Fill Plugs

M12 x 1.5
Torque Value
29 ft-lbs (39 N·m)
2

Transmission Fluid Drain/Fill Plug

M12 x 1.5
Torque Value
29 ft-lbs (39 N·m)

Transmission case

Secures the transmission case halves together and is critical for maintaining the transmission's internal pressure and preventing leaks.

1

Transmission Case Bolts

M16 x 1.5
Important Notes
Estimated torque values based on general industry standards.

Valve body

Secures the valve body to the transmission case and is essential for maintaining proper hydraulic pressure and transmission performance.

1

Valve Body Bolts

M12 x 1.5
Important Notes
Estimated torque values based on general industry standards.

Torque converter

Secures the torque converter to the transmission case and engine crankshaft, ensuring proper alignment and preventing movement or vibration that could affect transmission performance.

1

Torque Converter Bolts

M14 x 1.5
Important Notes
Estimated torque values based on general industry standards.

Transmission cooler lines

Connects the transmission cooler lines to the transmission case and radiator, and proper torque ensures a leak-free seal and prevents damage to the transmission cooler.

1

Transmission Cooler Line Fittings

M10 x 1.25
Important Notes
Estimated torque values based on general industry standards.

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

What is the recommended torque specification for the U660E transmission pan bolts?

The recommended torque specification for the U660E transmission pan bolts is 7.5 Nm (65 in-lbs). Ensure the transmission pan surface is clean and free of debris before tightening to avoid leaks.

Q2

How often should I check the torque on the U660E transmission bolts?

It is recommended to check the torque on the U660E transmission bolts during routine maintenance, such as during a transmission fluid change or every 30,000 miles. Always re-torque after any disassembly or repair.

Q3

Can over-tightening the transmission bolts cause damage?

Yes, over-tightening can strip threads, warp the transmission pan, or damage the sealing surface, leading to leaks. Always use a calibrated torque wrench and follow the manufacturer's specifications.

Q4

What should I do if I notice a leak after tightening the transmission pan bolts?

If a leak occurs, first verify that the bolts are torqued to the correct specification. If the issue persists, inspect the transmission pan gasket for damage or improper installation. Replace the gasket if necessary.

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

Digital Torque Wrench

A precision tool for applying accurate torque to transmission bolts.

  • Adjustable torque settings
  • Digital display for precise readings
Learn more

Torque Angle Gauge

Used to measure the angle of rotation when applying torque to bolts.

  • Magnetic base for easy attachment
  • Clear angle markings for accuracy
Learn more

Transmission Jack

A hydraulic jack designed to safely support and position the transmission during service.

  • Adjustable height and tilt
  • Secure locking mechanism
Learn more
Service Procedures

U660E Transmission Bolt Torque Application

Detailed steps for applying the correct torque to U660E transmission bolts.

  • Ensure the transmission is securely mounted on the transmission jack.
  • Clean the bolt threads and apply a small amount of thread locker if specified.
  • Using the digital torque wrench, tighten the bolts to the initial torque specification (e.g., 25 Nm).
  • Use the torque angle gauge to apply the final torque by rotating the bolts to the specified angle (e.g., 90 degrees).
  • Double-check all bolts to ensure they are properly torqued.
View full procedure

U660E Transmission Removal and Installation

Procedure for safely removing and reinstalling the U660E transmission.

  • Disconnect the battery and remove any components obstructing access to the transmission.
  • Support the transmission with the transmission jack and disconnect all electrical connectors and fluid lines.
  • Remove the transmission mounting bolts and carefully lower the transmission from the vehicle.
  • Install the new or serviced transmission by reversing the removal steps.
  • Torque all bolts to the specified values using the recommended tools.
View full procedure
Technical Service Bulletins

U660E Transmission Bolt Torque Specification Update

2018-05-15

Updated torque specifications for U660E transmission bolts to prevent over-tightening and potential damage.

2012-2020 Lexus GS

Resolution: Follow the revised torque specifications provided in the bulletin and use a calibrated torque wrench for accuracy.

U660E Transmission Fluid Leak Investigation

2019-11-22

Investigation into reports of fluid leaks from the U660E transmission due to improperly torqued bolts.

2012-2020 Lexus GS

Resolution: Inspect all transmission bolts for proper torque and re-torque as necessary. Replace any damaged seals or gaskets.

About the Author

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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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