What Are The Most Common Issues With Lexus RX300 Transmission?

Will my Lexus RX300 have any transmission issues down the load? Let's diagnose

The Lexus RX300 is the 1st generation luxury crossover in the United States. After many years, this car remains one of the best luxury SUVs for people.

Despite being such a world-class luxury car, it does have some issues with its trans. So here, in this write-up, we are going to discuss the Lexus RX300 transmission problems.

Lexus uses two variant models of transmission:

  • U140E
  • U140F

Lexus has some common issues with its transmission, which are mentioned as follows:

  • No Response Leakage
  • Fuel Running Low
  • Burning Smell
  • Shudder And Grinding
  • Clunking
  • Car Won’t Move In Gear
  • Issues With Torque Converter
  • Issues With The Valve Body
  • Noisy Transmission
  • Lose Gears
  • No Reverse
  • MIL
  • Dragging Of Clutch

Common Issues With Lexus RX300

The interior is more of a practical place with comfy front and rear seats and enough room for the passengers. This car provides many features and equipment, and if you wish, you can install the optional equipment as well.

The interior of this car is good, and most of its components are pretty durable, but there have been reports of cracked dashes. Some lucky people got it covered under their extended warranty period.

The fuel line of this car may start to rust, which can fuel leaks in the future. In addition, there have been reports of broken key shells, issues with opening/ closing the power tailgate. Not just these, people have reported excess headlight condensation, leading to headlight failure.

Another word is if you own such a car, you need to check the power steering fluid level regularly because there are numerous downside reviews to this. Also, the power steering line behind the engine can leak as well and sometimes burst.

Before we talk about the transmission problems, let us take a quick recap about how an automatic transmission works.

Issues With The Lexus RX300 Transmission

Here are some of the minor transmission issues that you can see in a Lexus RX300.

  • When your RX300 has a faulty transmission, you will get a burning odor while driving. It does not matter whether you drive at high speed or low; you will get a burning odor.
    This is because of the overheating effects of transmission. And when not treated, this can melt down the components installed in the gearbox and damage the entire transmission.
  • Driving around with a faulty transmission can produce unbearable noise. It will sound like something is getting ground. You can feel the vibration of the grinding on the brake and throttle pedals.
  • When you have faulty transmission, your vehicle will tend to eat up the fuel a lot faster. A bad transmission system can consume a lot of fuel but will not be working fine.
  • It can cause a value body failure. When a valve has worn out, the channel in there can get bigger and disrupt proper functioning. This results in slipping gears and fluid leaks. The valve issues are also termed garage shifts, as they delay the shifting procedure.
  • You may also experience a drag clutch. This happens when the clutch fails to let go of the engine when you let off the clutch pedal. This produces a noisy gear change and damages the gearbox and badly affects the transmission.
  • You will produce annoying noises when in neutral mode. This signifies problems with the transmission and should be fixed immediately.

Out of all, most issues are related to transmission liquid. To keep your car safe from these, you need to check the transmission oil regularly. Transmission is a vital system for your car and plays a crucial role in your car’s smooth functioning.

Common Issue With The Torque Converter

The torque converter is a fluid-based clutch between the engine and the transmission. It has several functions, which are listed as follows:

  • Transfers motions from the engine to the transmission.
  • Drives the oil pump in the gearbox.
  • Increases the torque from the crankshaft to transmission during the movement.
  • Operates as a flywheel neutralizing the oscillations and pulsations from the engine to the transmission.

But now, when your torque converter is not working properly, you will notice that the car cannot maintain the gear; it will slip.

When you have a bad torque converter, your car will begin to shake even when the speed is low. If not fixed, it can damage the entire system and can contaminate the transmission liquid.

The torque converter is affected when your car produces a higher amount of friction, and this friction will cause overheating.

You should get it to fix immediately.

Slipping Transmission: A Major Problem

Slipping transmission is a serious and common and major issue of the Lexus models, you know the transmission is failing when you try to throttle, but the car’s speed is not increasing at all. Instead, the engine is revving up, but your car is not moving faster.

so here I will be outlining some signs that can help you diagnose if you have a slipping transmission.

Pay Attention To The Gauges – Tachometer And Speedometer

You need to pay attention to these two, let me tell you why!

Put your car in drive and drive. Technically, when you push the gas pedal or acceleration pedal, your tachometer or RPM and speedometer should increase. This is because as the engine speed increases, the horse speed should increase, and the car will move faster now.

Now here’s what happens when your auto transmission is slipping. The transmission is what connects the engine to the wheels.

When the engine turns or powers up, the trans allows the power to be transferred to the wheels. If you have a faulty trans, the power will not be properly transferred from the engine to the wheels.

So, when you push the gas pedal, your tachometer will go up, but your speedometer will not follow up that quickly. So, your engine is just going to rev up, but the speed would barely increase.

To be sure of it, drive to a road with a lot of space and just push the gas pedal in. Your tachometer would just fly up, but your speedometer will barely move.

I recommend having someone with you and asking them to pay attention to the gauges while you drive the car. It is a simple test to know if your transmission is slipping.

Major Auto-Trans Shifting Problems

Now here, let me tell you about the four basic auto-trans shifting problems. This can help you find out if there is an issue with your automatic transmission problems.

Problem 1: Rough Shifting

So, if you are driving a car with an automatic transmission, and if the car is old and in fairly decent condition, you can have a rough shifting when you change gears.

Now, as the car is old, it will be slightly rough than normal. When you shift, you experience a shock; generally, it is because of low transmission fluid.

If that’s the case, the actual fluids need to be changed. If you experience rough shifts, you have to check the transmission fluids. Check the condition, see if it is old, see if it is low and if you do not what to do, ask a mechanic to help you out and see if that’s the issue.

However, most of the time, users experience this rough shifting because of low transmission fluid.

Problem 2: Car Will Not Shift Into Drive Or Reverse

The second problem with automatic transmission shifting is your car will not shift into drive or reverse. So, you actually cannot shift your car physically.

And once again, one of the main reasons for this is the transmission liquid. However, there are many reasons and many things that can pose this specific problem with the transmission.

There may be many other underlying causes, but I suggest you check on the transmission fluid first. There is also likely going to be a key slot right beside the shifter. If yes, take your car key, put it into the key slot and try to shift it into drive or reverse, and see if that helps.

If you do not see any such results, you have to dig deeper than that. But you might want to note as many symptoms as you can before figuring out the potential solution and spending your money on it. The more symptoms you have, the better the chances of getting a potential solution.

Problem 3: Car Will Not Start Or Respond

Now moving on to the third problem, which is your car does not respond or start? Then you might think that it is probably because of the battery, alternator. You might think that it is your starter, your key, or whatever the case is. You actually might have left your car in gear.

Yes, you might have left your automatic transmission in reverse, drive, low, sport, or 1, or 2, whatever your gear sector has. Basically, there is something called a Neutral Safety Switch.

Your neutral safety switch basically allows your engine to start when it is parked in neutral.

This means if you have left your car in whatever reverse or drive, anything other than the Neutral Safety Switch, then your engine will not start.

So, if your car does not start, take a quick look at the shifter, you shut your car off and went off to work, and you got your e-brake on so that your car does not roll away. So now, when you come back and if it does not start, you think your battery died.

Problem 4: Delayed Engagement

If you do not know what a late engagement feels like, here is how you will feel. If you put the car in drive, you push the gas pedal, and your car does not move instantly, and all of a sudden, it moves, literally, after a second or two. This is called the late or delayed engagement.

In other words, it is the late engagement of your drive or your reverse, or whatever case it is, or whatever gear you are putting it in.

Once again, this could be because of the low transmission fluid, or fluid needs to be changed, or it could also occur because of the worn seals or stretched-out bands within the transmission.

There are so many components, many small components in the transmission, like thousands of small parts. And when some of them are worn out, things can go rough with your transmission. And the late engagement is one of the potential problems that can arise.

Frequently Asked Questions

Q 1. Why Is Transmission Fluid So Important?

The transmission oil has three vital functions, which are:

  • Provides the necessary lubrication of the moving parts.
  • It helps in cooling down the components in the gearbox.
  • Takes part in the hydraulic system, which mechanically controls the parts in the gearbox.

Q 2. When Should I Get My Gearbox Diagnosed?

You should diagnose your gearbox under the following cases:

  • After 40,000 kilometers after the last diagnosis
  • In case you suspect deviation of performance from the normal performance of the gearbox.
  • If you purchased a pre-owned vehicle.

Q 3. How Do I Maintain My Auto-Trans System?

Maintenance often increases the lifespan of your transmission system. To maintain your auto-trans system, you should do these:

  • Change of transmission oil, as performance decreases over operating cycles and can lead to wearing of mechanism.
  • Replacement of oil and gasket.
  • Reset of the electronics used in the gearbox.
  • Adaptation (if needed).


So now you finally know about the Lexus RX300 transmission problems. These are very common with Lexus RX300 and RX330. Even vehicles with automatic transmission systems tend to face these issues.

Here in this write-up, I have shared and explained everything I researched. I have also explained the diagnostics, maintenance, structure of an automatic transmission system.

If you have a test on this, this write-up will surely help you score a 100. And, if you find anything suspicious with the transmission, let your mechanic handle it. These systems are very complicated and need professional hands.

Written by Yusuke Kohara

Hi there! My name is Yusuke. I write about automotive topics for Car Proper. I love cars and have a passion for writing helpful articles on tools, car accessories, and how-to to help my readers solve their problems. In my spare time, I'm either working out, reading the book, or spending time with my family. I also work for a digital consulting agency.

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