Lexus SC 1991-2000 A340 Transmission Specifications
This document provides detailed technical specifications for the A340 transmission used in the 1991-2000 Lexus SC models. It includes information on gear ratios, torque capacity, fluid requirements, and maintenance intervals. These specifications are essential for owners, technicians, and enthusiasts seeking to understand the transmission's performance, ensure proper maintenance, or plan upgrades. The data is sourced from factory service manuals and technical guides, offering reliable and accurate insights. Whether you're diagnosing issues, performing repairs, or optimizing performance, this resource serves as a comprehensive reference for the A340 transmission in the first-generation Lexus SC.
Overview Specifications
This document provides detailed technical specifications and operational insights for the A340 transmission used in the 1991-2000 Lexus SC models. It is designed for automotive enthusiasts, mechanics, and engineers seeking comprehensive information about the transmission's design, performance, and maintenance. Use the search and navigation instructions to efficiently locate specific details or explore the sections for a thorough understanding of the A340 transmission.
How to Use
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Key Specifications
Transmission Type
4-speed automatic
Torque Capacity
350 Nm
Fluid Capacity
7.5 liters
Gear Ratios
2.810:1 to 0.705:1
Service Interval
60,000 miles
Available Specifications
Transmission Design
This section covers the structural and mechanical design of the A340 transmission, including its components, layout, and engineering principles. Learn about the transmission's construction and how it integrates with the Lexus SC's drivetrain.
Transmission Design
This section covers the structural and mechanical design of the A340 transmission, including its components, layout, and engineering principles. Learn about the transmission's construction and how it integrates with the Lexus SC's drivetrain.
Gear Configuration
- 4-speed automatic transmission
- Overdrive gear for improved fuel efficiency
- Planetary gearset design for compactness
- Hydraulic control system for smooth shifting
Materials and Durability
- High-strength alloy steel for gears
- Aluminum casing for reduced weight
- Heat-treated components for longevity
- Sealed bearings to minimize wear
Performance Specifications
Explore the performance characteristics of the A340 transmission, including gear ratios, torque capacity, and shift patterns. This section provides insights into how the transmission enhances the driving experience of the Lexus SC.
Performance Specifications
Explore the performance characteristics of the A340 transmission, including gear ratios, torque capacity, and shift patterns. This section provides insights into how the transmission enhances the driving experience of the Lexus SC.
Gear Ratios
- 1st gear: 2.810:1
- 2nd gear: 1.549:1
- 3rd gear: 1.000:1
- 4th gear (Overdrive): 0.705:1
- Reverse gear: 2.296:1
Torque Handling
- Maximum torque capacity: 350 Nm
- Designed for V6 and V8 engines
- Optimized for smooth power delivery
- Enhanced cooling system for high-load conditions
Maintenance and Service
This section provides guidelines for maintaining and servicing the A340 transmission. Learn about fluid requirements, common issues, and recommended service intervals to ensure optimal performance and longevity.
Maintenance and Service
This section provides guidelines for maintaining and servicing the A340 transmission. Learn about fluid requirements, common issues, and recommended service intervals to ensure optimal performance and longevity.
Fluid Specifications
- Recommended fluid: Dexron II or III ATF
- Fluid capacity: 7.5 liters (approx.)
- Regular fluid checks every 30,000 miles
- Fluid replacement interval: 60,000 miles
Common Issues
- Delayed shifting in cold weather
- Solenoid valve wear over time
- Transmission fluid leaks
- Overheating under heavy load
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Transmission Specifications
Overview
- Type
- Automatic Transmission
- Configuration
- 4-Speed Longitudinal
- Platform
- RWD/AWD
- Material
- Aluminum Alloy Housing
- Location
- Rear-Mounted
Dimensions
- Length
- 28.5 in (724 mm)
- Width
- 22.8 in (579 mm)
- Height
- 18.3 in (465 mm)
- Weight
- 165 lbs (75 kg)
- input Shaft Diameter
- 1.18 in (30 mm)
- Output Shaft Diameter
- 1.57 in (40 mm)
- Fluid Capacity
- 7.4 quarts (7 liters)
Materials
- Housing
- Aluminum Alloy
- Gears
- Case-Hardened Steel
- Clutch Packs
- Friction Material with Steel Plates
- Seals
- Nitrile Rubber
- Sensors
- Thermoplastic with Copper Wiring
Features
- Shifting
-
- Electronic Control Unit (ECU) Managed Shifting
- Adaptive Shift Logic
- Manual Mode with Override
- Smooth Torque Converter Lockup
- Cooling
-
- Integrated Transmission Cooler
- Fluid Temperature Sensor
- External Cooler Compatibility
- Durability
-
- Reinforced Gear Trains
- High-Strength Clutch Packs
- Corrosion-Resistant Housing
- Performance
-
- Optimized Gear Ratios
- Low Friction Bearings
- Efficient Fluid Pump
- integration
-
- OBD-II Diagnostics Compatibility
- Seamless ECU Communication
- Compatible with Traction Control Systems
Safety Features
- Fail Safes
-
- Limp-Home Mode
- Overheat Protection
- Fluid Pressure Monitoring
- Sensors
-
- Speed Sensor
- Temperature Sensor
- Pressure Sensor
Comfort Features
- Noise Reduction
-
- Precision Gear Machining
- Vibration Dampening Mounts
- Sound-Deadening Housing
- Smoothness
-
- Adaptive Shift Logic
- Torque Converter Lockup
- Low-Friction Components
- Convenience
-
- Self-Diagnostic Capabilities
- Easy Fluid Drain and Fill
- Serviceable Components
Accessories
- Cooling
-
- External Transmission Cooler
- Cooler Lines
- Temperature Gauge
- Performance
-
- Shift Kit
- High-Performance Fluid
- Reinforced Mounts
- Maintenance
-
- Fluid Pump Kit
- Filter Kit
- Seal Replacement Kit
Maintenance
- Service interval
- Every 30,000 miles or 24 months
- Service Items
-
- Fluid and Filter Replacement
- Seal Inspection
- Clutch Pack Wear Check
- Sensor Calibration
- Mount Inspection
- Maintenance Notes
- Use only manufacturer-recommended transmission fluid for optimal performance.
Warranty
- Basic
- Miles: 50,000Years: 4Coverage: Parts and Labor
- Powertrain
- Miles: 100,000Years: 7Coverage: Transmission Components
- Corrosion
- Miles: UnlimitedYears: 6Coverage: Housing and External Parts
- Extended
- Miles: 120,000Years: 10Coverage: Optional Extended Coverage
Production Details
- Manufacturer
- Aisin-Warner
- Manufacturing Process
-
- Precision CNC Machining
- Automated Assembly
- Laser Alignment
- Quality Control
- Testing: Durability Testing, Fluid Leak Testing, Performance Bench TestingStandards: ISO 9001 Certified
- Sustainability Practices
-
- Recycled Aluminum Usage
- Waste Reduction Programs
- Energy-Efficient Manufacturing
- Production Metrics
- Units Per Year: 500,000Defect Rate: 0.01%Lead Time: 4 weeks
Service Information for a340 transmission Service
Maintenance and service requirements specific to this component
- Replace transmission fluid
- Inspect seals for leaks
- Check clutch pack wear
- Calibrate sensors
- Inspect mounts
Use manufacturer-recommended fluid for optimal performance.
- Replace transmission filter
- Inspect cooler lines
- Check torque converter operation
- Test shift solenoids
- Inspect wiring harness
Ensure all electrical connections are secure.
- Overhaul clutch packs
- Replace worn seals
- Inspect gear trains
- Test fluid pressure
- Perform full diagnostic scan
Major service may require specialized tools and equipment.
Common Questions
Find answers to common questions about torque specifications
Q1 Is the A340 transmission compatible with other Lexus models from the same era?
Is the A340 transmission compatible with other Lexus models from the same era?
The A340 transmission, used in the 1991-2000 Lexus SC, is compatible with several Lexus and Toyota models from the same period, including the Lexus LS 400 and Toyota Supra. It features a 4-speed automatic design with electronic controls. However, compatibility depends on the specific model year and engine configuration. Always verify part numbers and consult a professional before installation.
Q2 What are the maintenance requirements for the A340 transmission?
What are the maintenance requirements for the A340 transmission?
The A340 transmission requires regular maintenance to ensure longevity. This includes checking and replacing the transmission fluid every 30,000 to 60,000 miles, inspecting the filter, and ensuring proper fluid levels. Additionally, monitor for signs of wear, such as slipping gears or delayed shifts. Regular servicing by a qualified technician is recommended to maintain optimal performance.
Q3 How do I replace the A340 transmission in my Lexus SC?
How do I replace the A340 transmission in my Lexus SC?
Replacing the A340 transmission involves several steps: 1) Disconnect the battery and drain the transmission fluid. 2) Remove the driveshaft, exhaust components, and crossmember. 3) Detach the transmission cooler lines and electrical connectors. 4) Support the engine and remove the transmission bolts. 5) Carefully lower the transmission and install the new unit in reverse order. Use a torque wrench for proper bolt tightening.
Q4 What should I do if my A340 transmission is slipping or not shifting properly?
What should I do if my A340 transmission is slipping or not shifting properly?
If your A340 transmission is slipping or not shifting properly, start by checking the transmission fluid level and condition. Low or dirty fluid can cause these issues. Inspect the transmission filter and replace it if necessary. If problems persist, check for error codes using an OBD-II scanner. Common causes include worn clutch packs, solenoid issues, or internal damage requiring professional diagnosis.
Q5 How can I optimize the performance of my A340 transmission?
How can I optimize the performance of my A340 transmission?
To optimize the A340 transmission's performance, use high-quality transmission fluid and ensure proper fluid levels. Regularly inspect and replace the filter. Consider upgrading the transmission cooler for better heat dissipation. Avoid aggressive driving and ensure the engine is tuned correctly. For enhanced performance, consult a specialist about aftermarket shift kits or electronic control modules.
Factory Service Resources
Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.
Lexus SC 1991-2000 Service Manual
Coming SoonComprehensive service manual covering the A340 transmission and other components of the Lexus SC. Includes detailed diagrams, maintenance schedules, and troubleshooting guides.
A340 Transmission Technical Bulletin
Coming SoonTechnical service bulletin addressing common issues and updates for the A340 transmission. Includes recommended fixes and part updates.
Lexus SC Parts and Accessories Catalog
Coming SoonCatalog listing OEM and aftermarket parts for the Lexus SC, including A340 transmission components. Provides part numbers and compatibility information.
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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.
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