The A340E is a 4-speed automatic transmission developed by Aisin Warner and widely used in Toyota, Lexus, and some Jeep models. Known for its durability and smooth performance, this transmission has been a favorite in both passenger cars and off-road vehicles. In this article, we will explore its specifications, applications, common issues, and maintenance tips.

1. Overview of the A340E Transmission

The A340E was first introduced in the 1980s and remained in production for several decades due to its reliability and adaptability. It is designed for rear-wheel-drive (RWD) and four-wheel-drive (4WD) applications and features an electronically controlled shifting system.

The “E” in A340E stands for “Electronic Control,” meaning that the gear shifts are managed by a Transmission Control Unit (TCU) rather than being purely hydraulic like older automatic transmissions.

Key Features:

✅ Electronically controlled shifting for precise gear changes
✅ Hydraulic torque converter for smoother acceleration
✅ Overdrive function for better fuel economy
✅ Durable planetary gearset design for high torque handling

2. A340E Transmission Specifications

Feature	Details
Manufacturer	Aisin Warner
Type	4-speed automatic
Gear Ratios	1st: 2.804, 2nd: 1.531, 3rd: 1.000, 4th: 0.705, Reverse: 2.393
Torque Capacity	~280-300 lb-ft (varies by model)
Fluid Type	Toyota Type T-IV or Dexron III ATF
Control System	Electronically controlled solenoids
Applications	RWD and 4WD vehicles

3. Vehicles Using the A340E Transmission

The A340E transmission has been installed in many popular Toyota, Lexus, and Jeep models.

🚗 Toyota Models:

Toyota Supra (1986-1998)
Toyota Tacoma (1995-2004)
Toyota 4Runner (1988-2002)
Toyota Land Cruiser (1989-1997)
Toyota Cressida (1986-1992)
Toyota Soarer (1986-2001)

🚙 Lexus Models:

Lexus SC 300 (1991-2000)
Lexus GS 300 (1993-1997)
Lexus LS 400 (1989-1994)

🚜 Other Applications:

Jeep Cherokee XJ (with 4.0L engine, 1987-2001)
Volvo 960 (1995-1997, under Aisin Warner AW30-40LE badge)

4. Common Problems with the A340E Transmission

Despite being a strong and reliable transmission, the A340E can develop issues over time due to wear and tear, fluid degradation, or electronic malfunctions.

1. Harsh or Delayed Shifting

🔴 Symptoms:

Hard or jerky shifts
Delayed gear engagement

🔧 Causes & Solutions:
✔ Dirty or low ATF fluid → Check and replace with Toyota T-IV ATF
✔ Faulty shift solenoids → Replace damaged solenoids
✔ Worn-out valve body → Rebuild or replace the valve body

2. Overheating Issues

🔥 Symptoms:

Transmission warning light on the dashboard
Burnt smell from transmission fluid
Slipping gears

🔧 Causes & Solutions:
✔ Low transmission fluid → Check and top up with the correct ATF
✔ Blocked transmission cooler → Flush or replace the transmission cooler
✔ Heavy towing or off-road use → Install an aftermarket transmission cooler

3. Torque Converter Problems

⚠️ Symptoms:

Shuddering or vibrations during acceleration
Poor fuel economy
Slipping at highway speeds

🔧 Causes & Solutions:
✔ Faulty torque converter → Replace the torque converter
✔ Contaminated ATF fluid → Flush and refill transmission

4. Slipping Gears or Stuck in Limp Mode

🚨 Symptoms:

Transmission slips between gears
Stuck in 2nd or 3rd gear only

🔧 Causes & Solutions:
✔ Faulty solenoids → Replace malfunctioning shift solenoids
✔ ECU problem → Reset or reprogram the Transmission Control Unit (TCU)

5. Reverse Gear Failure

🔴 Symptoms:

No response when shifting into reverse
Delayed engagement in reverse

🔧 Causes & Solutions:
✔ Worn reverse clutch pack → Requires a transmission rebuild
✔ Valve body malfunction → Replace or rebuild the valve body

5. Maintenance Tips for the A340E Transmission

To extend the life of your A340E transmission, follow these maintenance tips:

✅ 1. Regular Fluid Changes

Use Toyota Type T-IV ATF or Dexron III
Change every 30,000-50,000 miles
Check fluid level and condition regularly

✅ 2. Keep the Cooling System Clean

Flush the transmission cooler every 60,000 miles
Install an auxiliary transmission cooler if towing frequently

✅ 3. Avoid Heavy Loads

Avoid excessive towing beyond your vehicle’s rated towing capacity

✅ 4. Drive Smoothly

Avoid sudden acceleration and aggressive shifting

6. Differences Between A340E, A340F, and A340H

There are different versions of the A340 transmission:

Model	Drive Type	Main Difference
A340E	RWD	Electronically controlled, used in passenger cars
A340F	4WD	Found in SUVs like Toyota 4Runner
A340H	4WD	Hydraulic controlled, used in some older Land Cruisers

Conclusion: Is the A340E a Reliable Transmission?

Yes! The A340E transmission is known for its strong design and durability, making it an excellent choice for Toyota trucks, SUVs, and performance cars. However, proper maintenance is essential to prevent common issues like overheating, solenoid failures, and slipping gears.

📌 Key Takeaways:
✔ Change transmission fluid regularly
✔ Check for leaks and overheating issues
✔ Replace solenoids or torque converter if needed
✔ Use an aftermarket cooler for towing or off-road driving

Would you like troubleshooting help for your A340E transmission? 🚗

A340E Transmission Repair Manual PDF

A340E Download