Subaru Subaru Legacy 2004-2008 Drivetrain Specifications
Explore the detailed drivetrain specifications for the 2004-2008 Subaru Legacy, including transmission types, AWD system, and differential configurations. Ideal for maintenance, repairs, and performance upgrades.
Overview Specifications
This document provides detailed specifications and technical information about the drivetrain of the 2004-2008 Subaru Legacy. It is designed to assist enthusiasts, mechanics, and owners in understanding the vehicle's drivetrain components, configurations, and performance characteristics. Use the search functionality to locate specific terms or navigate through sections to explore detailed information about transmission types, differential systems, and other drivetrain features.
How to Use
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Scroll through the document or use the table of contents to jump to specific sections. Each section is organized into subsections with detailed technical points for easy reference.
Key Specifications
Transmission Options
5-speed manual, 4-speed automatic
AWD System
Symmetrical AWD with viscous coupling
Final Drive Ratio
4.111
Torque Split
50/50 front-to-rear
Differential Type
Open (standard), Limited-slip (optional)
Available Specifications
Transmission Systems
This section covers the transmission options available for the 2004-2008 Subaru Legacy, including manual and automatic variants. It provides details on gear ratios, shift mechanisms, and performance characteristics.
Transmission Systems
This section covers the transmission options available for the 2004-2008 Subaru Legacy, including manual and automatic variants. It provides details on gear ratios, shift mechanisms, and performance characteristics.
Manual Transmission
- 5-speed manual transmission standard on most trims
- Gear ratios: 1st (3.454), 2nd (1.947), 3rd (1.366), 4th (0.972), 5th (0.738)
- Final drive ratio: 4.111
- Dual-mass flywheel for smoother engagement
- Short-throw shifter available on GT models
- Hydraulic clutch system for precise control
Automatic Transmission
- 4-speed automatic with Sportshift option
- Gear ratios: 1st (2.785), 2nd (1.545), 3rd (1.000), 4th (0.694)
- Final drive ratio: 4.111
- Electronic control for adaptive shifting
- Manual mode allows driver-controlled shifts
- Torque converter with lock-up clutch
All-Wheel Drive (AWD) System
This section explains the Symmetrical All-Wheel Drive system used in the 2004-2008 Subaru Legacy. It includes details on the system's design, operation, and benefits for traction and stability.
All-Wheel Drive (AWD) System
This section explains the Symmetrical All-Wheel Drive system used in the 2004-2008 Subaru Legacy. It includes details on the system's design, operation, and benefits for traction and stability.
Symmetrical AWD Design
- Equal-length driveshafts for balanced power distribution
- Full-time AWD system with no driver input required
- Center differential with viscous coupling
- Torque split: 50/50 front-to-rear under normal conditions
- Automatic torque redistribution during slippage
- Enhanced stability in all weather conditions
Performance Benefits
- Improved traction on wet, icy, or uneven surfaces
- Reduced wheel spin during acceleration
- Enhanced cornering stability and control
- Better weight distribution for handling
- Compatible with Subaru's Vehicle Dynamics Control (VDC)
- Low maintenance requirements
Differential Systems
This section details the differential systems used in the 2004-2008 Subaru Legacy, including front, rear, and center differentials. It highlights their roles in power distribution and handling.
Differential Systems
This section details the differential systems used in the 2004-2008 Subaru Legacy, including front, rear, and center differentials. It highlights their roles in power distribution and handling.
Front and Rear Differentials
- Open differentials standard on most models
- Limited-slip differential available on GT trims
- Helical gear design for smooth operation
- Sealed units for reduced maintenance
- Compatible with AWD system for optimal performance
- Durable construction for long-term reliability
Center Differential
- Viscous coupling for automatic torque distribution
- 50/50 torque split under normal driving conditions
- Adjusts torque bias during wheel slip
- Sealed unit with no user adjustments required
- Integrated with transmission for compact design
- Enhances off-road and low-traction performance
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Component Specifications
Overview
- Type
- All-Wheel Drive (AWD)
- Configuration
- Symmetrical AWD
- Platform
- Subaru Legacy Platform
- Material
- Aluminum and Steel
- Location
- Front-engine, longitudinal
Dimensions
- Transmission Length
- 28.5 inches (724 mm)
- Driveshaft Diameter
- 2.5 inches (63.5 mm)
- Differential Width
- 18.7 inches (475 mm)
- Axle Length
- 31.1 inches (790 mm)
- Transfer Case Height
- 9.8 inches (249 mm)
- Propeller Shaft Length
- 45.3 inches (1150 mm)
- Wheelbase
- 105.1 inches (2670 mm)
Materials
- Transmission Housing
- Aluminum alloy
- Driveshaft
- High-strength steel
- Differential Case
- Cast iron
- Axles
- Forged steel
- Transfer Case
- Aluminum alloy
Features
- Transmission
-
- 5-speed manual
- 4-speed automatic
- 5-speed automatic (optional)
- Electronic throttle control
- Differential
-
- Limited-slip rear differential
- Open front differential
- Torque vectoring (optional)
- Active torque split
- Driveshaft
-
- Balanced for high-speed operation
- Heat-treated steel
- U-joint design
- Axles
-
- CV joints
- High-angle articulation
- Sealed for life
- Transfer Case
-
- Chain-driven
- Sealed unit
- Oil-cooled
Safety Features
- Stability Control
-
- Vehicle Dynamics Control (VDC)
- Traction Control System (TCS)
- Braking
-
- ABS with EBD
- Hill-start assist
- Structural
-
- Reinforced driveshaft tunnel
- Crash-resistant differential mounts
Comfort Features
- Noise Reduction
-
- Insulated transmission tunnel
- Balanced driveshaft
- Vibration Control
-
- Hydraulic engine mounts
- Dual-mass flywheel
- Handling
-
- Predictable torque distribution
- Smooth gear shifts
Accessories
- Upgrades
-
- Performance clutch kit
- Short-throw shifter
- Heavy-duty driveshaft
- Maintenance Tools
-
- Differential fluid pump
- Transmission jack
- Torque wrench set
- Protection
-
- Skid plates
- Differential guard
- Driveshaft loop
Maintenance
- Service interval
- Every 30,000 miles or 24 months
- Service Items
-
- Transmission fluid change
- Differential fluid change
- Driveshaft inspection
- CV joint lubrication
- Transfer case fluid check
- Maintenance Notes
- Use only Subaru-approved fluids for optimal performance.
Warranty
- Basic
- Miles: 36,000Years: 3Coverage: Bumper-to-bumper
- Powertrain
- Miles: 60,000Years: 5Coverage: Drivetrain components
- Corrosion
- Miles: UnlimitedYears: 5Coverage: Perforation only
- Roadside Assistance
- Miles: 36,000Years: 3Coverage: 24/7 support
Production Details
- Manufacturer
- Subaru Corporation
- Manufacturing Process
-
- Precision casting
- CNC machining
- Heat treatment
- Dynamic balancing
- Quality Control
- inspection: 100% component testingTolerances: ±0.001 inches
- Sustainability Practices
-
- Recycled aluminum usage
- Low-emission manufacturing
- Production Metrics
- Units Per Day: 500Defect Rate: 0.01%
Service Information for drivetrain Service
Maintenance and service requirements specific to this component
- Inspect driveshaft for wear
- Check differential fluid level
- Lubricate CV joints
- Inspect transmission mounts
- Check transfer case fluid
Ensure all fluids are at operating temperature before checking levels.
- Replace differential fluid
- Replace transmission fluid
- Inspect U-joints
- Check axle seals
- Test VDC system
Use Subaru Extra-S gear oil for differentials.
- Replace driveshaft if necessary
- Overhaul transfer case
- Inspect and replace CV boots
- Check alignment of drivetrain components
- Perform full system diagnostics
Major service may require specialized tools and equipment.
Frequently Asked Questions
Find answers to common questions about torque specifications
Q1 What drivetrain options are available for the 2004-2008 Subaru Legacy?
What drivetrain options are available for the 2004-2008 Subaru Legacy?
The 2004-2008 Subaru Legacy offers two primary drivetrain options: a standard Symmetrical All-Wheel Drive (AWD) system and a 5-speed manual or 4-speed automatic transmission. The AWD system ensures balanced power distribution for improved traction and stability. Compatibility varies by trim level, with the GT and 3.0R models featuring enhanced performance components.
Q2 What are the maintenance requirements for the Legacy's drivetrain?
What are the maintenance requirements for the Legacy's drivetrain?
Regular maintenance for the Legacy's drivetrain includes checking and replacing transmission fluid every 30,000-60,000 miles, inspecting the driveshaft and differential for wear, and ensuring proper alignment. The AWD system requires periodic lubrication of components and inspection of the transfer case. Adhering to the manufacturer's schedule ensures optimal performance and longevity.
Q3 How do I replace the drivetrain components on a 2004-2008 Subaru Legacy?
How do I replace the drivetrain components on a 2004-2008 Subaru Legacy?
To replace drivetrain components, first, lift the vehicle securely. Remove the driveshaft by unbolting it from the differential and transmission. For the differential, drain the fluid, unbolt the housing, and replace it with a new unit. Reassemble in reverse order, ensuring proper torque specifications. Always consult the service manual for detailed instructions.
Q4 What should I do if my Legacy's AWD system is malfunctioning?
What should I do if my Legacy's AWD system is malfunctioning?
If the AWD system malfunctions, check for error codes using an OBD-II scanner. Inspect the transfer case fluid level and condition. Ensure the tires are evenly worn and properly inflated. If issues persist, inspect the AWD control module and wiring. Common solutions include fluid replacement, sensor repair, or module replacement.
Q5 How can I optimize the performance of my Legacy's drivetrain?
How can I optimize the performance of my Legacy's drivetrain?
To optimize drivetrain performance, use high-quality synthetic transmission and differential fluids. Upgrade to performance-oriented components like a short-throw shifter or limited-slip differential. Regularly inspect and maintain the drivetrain to prevent wear. Proper alignment and tire selection also enhance traction and handling.
Factory Service Resources
Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.
2004-2008 Subaru Legacy Service Manual
Coming SoonComprehensive guide covering drivetrain maintenance, repair, and troubleshooting for the 2004-2008 Subaru Legacy.
Subaru Technical Service Bulletin: Drivetrain Updates
Coming SoonDetails updates and fixes for drivetrain-related issues in the 2004-2008 Subaru Legacy.
Subaru Legacy Parts and Accessories Catalog
Coming SoonCatalog listing OEM and aftermarket drivetrain parts and accessories for the 2004-2008 Subaru Legacy.
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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.
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