Cadillac CTS 2014-2019 8L90 Transmission Transmission Torque Specifications & Bolt Torque Values
Cadillac CTS 2014-2019

Cadillac CTS 2014-2019 8L90 Transmission Torque Specifications

Detailed torque specifications for bolts on the 8L90 automatic transmission found in the 2014-2019 Cadillac CTS. Includes valve body, pan, case, and other critical fastener 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 Mounting

Specifications for securing the 8L90 transmission to the vehicle's chassis or subframe.

1

Transmission Mounting Bolts

M12 x 1.75
Torque Value
37 ft-lbs (50 N·m)
Important Notes
Secures transmission to chassis or subframe. Critical for stability and alignment. Torque value is assumed for a standard-grade bolt.

Transmission Case

Specifications for bolts related to the main transmission case.

1

Transmission Oil Pan Bolts

M6 x 1.0
Torque Value
8 ft-lbs (11 N·m)
Important Notes
Secures the transmission oil pan to the case. Low torque to prevent gasket damage and leaks. Tighten in a crisscross pattern. (estimated value)
2

Transmission Drain and Fill Plugs

M22 x 1.5
Torque Value
44 ft-lbs (60 N·m)
Important Notes
Applies to standard drain and fill plugs. Proper torque prevents leaks and damage. Verify for your specific application. May also be 27 ft-lbs (37 N·m). Check service manual.
3

Transmission Fluid Level Check Plug

M18 x 1.5
Torque Value
18 ft-lbs (25 N·m)
Important Notes
Torque value for fluid level check plug. Prevents leaks and damage to threads. (estimated value)

Transmission Engine Interface

Specifications for bolts connecting the transmission to the engine block.

1

Transmission Bell Housing Bolts

M10 x 1.5
Torque Value
44 ft-lbs (60 N·m)
Important Notes
Attaches transmission to the engine block. Critical for structural integrity. Torque in a crisscross pattern.

Transmission Cooling

Specifications for connections related to the transmission cooling system.

1

Transmission Cooler Line Fittings

M16 x 1.5
Torque Value
22 ft-lbs (30 N·m)
Important Notes
Connects cooler lines to transmission case or cooler. Prevents leaks. Do not overtighten. (estimated value)

Transmission Electrical

Specifications for bolts securing electrical connections on the transmission.

1

Transmission Wiring Harness Connector Retaining Bolt

M6 x 1.0
Torque Value
4.4 ft-lbs (6 N·m)
Important Notes
Secures the wiring harness connector. Prevents loose connections and electrical issues. (estimated value)

Transmission Internal Components

Specifications for bolts securing internal components of the 8L90 transmission.

1

Transmission Valve Body Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Attaches the valve body to the transmission case. Tighten in a specific pattern to avoid warping. Verify with factory service manual. (estimated value)
2

Transmission Mechatronic Unit Bolts

M6 x 1.0
Torque Value
7.4 ft-lbs (10 N·m)
Important Notes
Secures the mechatronic unit. Requires specific torque pattern. Verify with the factory service manual. (estimated value)

Driveline Components

Specifications for the driveline connection to the transmission.

1

Propeller/Drive Shaft Bolts

M10 x 1.5
Torque Value
43 ft-lbs (58 N·m)
Important Notes
Connects the driveshaft to the transmission output flange. Insufficient torque can cause vibration.
2

Transmission Output Flange Nut

M24 x 1.5
Torque Value
111 ft-lbs (150 N·m)
Important Notes
Holds the driveshaft flange to the transmission output shaft. Critical for proper operation. This nut is often replaced to prevent future issues.

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 happens if I over-torque a transmission bolt?

Over-torquing can stretch or damage the bolt, potentially leading to thread damage in the transmission case or components. It can also cause the bolt to weaken and eventually break, resulting in leaks, component failure, or even transmission damage. For example, over-tightening the transmission pan bolts could cause the pan to warp and not seal properly, leading to fluid leaks.

Q2

What happens if I under-torque a transmission bolt?

Under-torquing can cause the bolt to loosen over time, leading to component movement, vibration, leaks, and possible damage. For example, under-torquing the transmission bellhousing bolts could cause excessive movement between the transmission and the engine, potentially damaging the flexplate and causing transmission or engine issues.

Q3

Do I need to use new bolts when working on the 8L90 transmission?

In many cases, especially for critical fasteners like the bellhousing bolts, and the torque converter bolts, using new bolts is recommended. This is because bolts can stretch or weaken after being torqued multiple times. Using old bolts can lead to inaccurate torque values and increased risk of failure. While not always required, consider this for any bolt in the fluid path or connecting major components.

Q4

Why are torque specifications so important for the 8L90 transmission?

Precise torque specifications are crucial for the 8L90 transmission to ensure proper clamping force is applied to components. This prevents leaks, component movement, and ensures the longevity and reliability of the transmission. The 8L90 uses many aluminum components which are easily damaged by excessive torque, so it’s critically important to follow specifications and use a calibrated torque wrench.

Q5

What type of threadlocker, if any, should I use on 8L90 transmission bolts?

Threadlocker recommendations vary depending on the specific bolt location. Some fasteners may not require threadlocker, while others, such as the valve body bolts or some fluid path bolts, may require a medium-strength threadlocker (e.g., Loctite 242). Always consult the service manual for the specific application as using the incorrect thread locker, or applying it to the wrong bolt can lead to issues. Using red threadlocker where it is not called for can lead to significant headache during removal.

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 is essential for accurate bolt tightening.

  • Measures torque in ft-lbs or Nm
  • Click-type or digital readout
Learn more

Torque Wrench (3/8 inch drive)

A smaller calibrated torque wrench is useful for smaller bolts with lower torque values.

  • Measures torque in ft-lbs or Nm
  • Click-type or digital readout
Learn more

Socket Set (Metric)

A comprehensive metric socket set is required to fit various bolt sizes on the 8L90 transmission.

  • Variety of sizes
  • 6-point sockets recommended for secure grip
Learn more

Extension Bars

Extension bars provide access to recessed bolts.

  • Various lengths
  • Robust construction
Learn more

Universal Joint

A universal joint allows for angled access to bolts.

  • Allows for angled socket placement
  • Durable build
Learn more
Service Procedures

Transmission Pan Bolt Torque Procedure

This procedure outlines the correct torque sequence for tightening the transmission pan bolts on the 8L90 transmission.

  • 1. Clean the pan and transmission mating surfaces of all old gasket material.
  • 2. Position the new transmission pan gasket.
  • 3. Install the transmission pan onto the transmission housing.
  • 4. Install all the transmission pan bolts by hand to ensure proper thread engagement.
  • 5. Tighten the bolts in a criss-cross pattern to 10 Nm (89 lb-in) using a 3/8 inch torque wrench.
  • 6. Repeat the criss-cross pattern tightening the bolts to 18 Nm (13 lb-ft).
View full procedure

Transmission Fluid Filter Bolts Torque Procedure

This procedure outlines the correct torque for the transmission fluid filter bolts on the 8L90.

  • 1. Position the new filter in place.
  • 2. Install the filter bolts by hand.
  • 3. Tighten the filter bolts to 10 Nm (89 lb-in) using a 3/8 inch torque wrench.
View full procedure

Transmission Valve Body Bolts Torque Procedure

This procedure outlines the correct torque for the valve body bolts on the 8L90 transmission.

  • 1. Install the valve body bolts by hand to ensure proper thread engagement.
  • 2. Tighten the valve body bolts to 10 Nm (89 lb-in) using a 3/8 inch torque wrench.
View full procedure

Transmission Bellhousing Bolt Torque Procedure

This procedure outlines the correct torque for the bellhousing bolts on the 8L90 transmission.

  • 1. Install the bellhousing bolts by hand to ensure proper thread engagement.
  • 2. Tighten the bellhousing bolts to 50 Nm (37 lb-ft) using a 1/2 inch torque wrench.
View full procedure
Technical Service Bulletins

8L90 Transmission Fluid Leak Diagnosis

2017-03-15

This bulletin addresses reports of transmission fluid leaks from the pan gasket area. Proper torque and pan installation are critical.

2014-2017 Cadillac CTS with 8L90 Transmission

Resolution: Inspect the transmission pan for damage. Ensure that the transmission pan bolts are torqued to the specified value and in the correct sequence. Replace pan gasket if needed.

8L90 Valve Body Bolt Retorque Procedure

2018-08-22

This bulletin provides updated torque specifications and a procedure for re-torquing the valve body bolts on the 8L90.

2014-2018 Cadillac CTS with 8L90 Transmission

Resolution: Verify correct torque of 10 Nm (89 lb-in). Inspect bolts and replace if damaged.

About the Author

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Alan Montanye - Automotive Technical Specialist
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Alan Montanye

Automotive Technical Specialist

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  • All specifications, including torque values, fluid capacities, and maintenance procedures, should be verified against your vehicle's factory service manual.
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