What transmission is in the LS400?
The LS400 uses a four-speed automatic transmission with electronic control, commonly referred to as the A340E. It is paired with the 1UZ-FE 4.0-liter V8 and drives the rear wheels.
In more detail, the Lexus LS400 — the original flagship sedan from Lexus — was engineered for smooth highway cruising and long-term reliability. The transmission is a core part of that design, delivering seamless shifts and predictable performance that defined the model’s early reputation for comfort and durability.
Transmission basics
Here are the core characteristics you should know about the LS400's transmission.
- Type: Four-speed automatic with electronic control (ECT)
- Drive layout: Rear-wheel drive (RWD)
- Engine pairing: 1UZ-FE 4.0-liter V8
- Transmission code and origin: A340E, built by Aisin-Warner for Toyota/Lexus
These features collectively define the LS400’s smooth power delivery and reliability ethos during its era.
Variants, evolution, and compatibility
Notes on how this transmission appears across the LS400’s production and how it relates to other Toyota/Lexus 4-speed automatics.
- Consistent 4-speed configuration across the first-generation LS400 (late 1980s to mid-1990s in most markets)
- Electronically controlled shift programming (ECT) for smoother gear changes
- Interchange and compatibility primarily within early Toyota/Lexus vehicles using the A340E family
In practice, owners and restorers typically pursue standard A340E maintenance practices and related service bulletins when issues arise.
Maintenance and common issues
Maintaining the LS400’s transmission helps preserve performance and longevity. The list below highlights typical care steps and potential problems observed in aging units.
- Regular transmission fluid checks and changes using the manufacturer-recommended ATF (often Toyota/Lexus WS)
- Monitor for slipping, harsh or delayed shifts, or rough engagement as early warning signs
- Inspect for fluid leaks around the pan, seals, and transmission cooler lines
- Consider professional diagnosis for electronic shift control or valve-body concerns
Proper maintenance can help mitigate common wear and tear, preserving the LS400’s characteristic smooth driving feel.
Summary
The LS400 relies on a four-speed automatic with electronic control (A340E) to deliver a smooth, reliable driving experience that matched the luxury sedan’s priorities of comfort and durability. For restoration or maintenance, focusing on correct ATF, leak prevention, and timely service is key to longevity.
What type of transmission does a Lexus have?
Lexus uses several types of transmissions depending on the model, including traditional automatic transmissions with multiple gears (e.g., 8-speed) and different kinds of continuously variable transmissions (CVTs). For hybrid models, they use an electronically controlled CVT (eCVT) which is a different system that uses a power split device instead of a belt. Some non-hybrid models also feature a unique Direct Shift-CVT (DCVT) which combines elements of traditional CVTs with a physical first gear for improved durability.
Types of transmissions Lexus uses
- Electronically controlled Continuously Variable Transmission (eCVT): Found in Lexus hybrid models, this system is fundamentally different from a belt-driven CVT. It uses a planetary gear set to manage power flow and is known for its reliability and smooth, seamless acceleration from electric motors.
- Direct Shift-CVT (DCVT): This is a unique type of CVT found in some non-hybrid Lexus and Toyota vehicles, such as the Lexus UX. It features a physical first gear for initial acceleration, which helps manage torque stress on the CVT belt, making it more durable than a traditional belt-driven CVT.
- Traditional Automatic Transmissions: Lexus also uses conventional automatic transmissions with a fixed number of gears, such as an 8-speed automatic in models like the ES 350.
- Older Transmissions: Some older models may have used transmissions with fewer gears, like the 4-speed or 5-speed automatics found in earlier RX or ES generations.
What drivetrain is the LS400?
Drivetrain
| Transmission | 5-speed automatic |
|---|---|
| Drive type | Rear wheel drive |
What transmission is in a LS400?
The LS 400's new 4.0-litre 1UZ-FE 32-valve V8 engine, capable of 245 PS (180 kW; 242 hp) and 350 N⋅m (258 lb⋅ft) of torque, was linked to a new four-speed automatic transmission with ECT-i electronically controlled shifts, super-flow torque converter and rear differential.
What makes the LS400 so special?
LS400. So what made it. Great. It all starts with the original petrol V8 dual overhead cam. And just smooth as butter to drive it was made to a four-speed automatic transmission.
