2018 Silverado 6 Speed Transmission Problems: The Reasons & Fixes

In a vehicle, most people look for more gears as it makes the car smoother overall. Because of this, 6-speed transmissions are popular. So trucks like the 2018 Chevy Silverado also use it to meet everyone’s demands.

But what are the 2018 Silverado 6 speed transmission problems? With the 2018 model of the Silverado, you might experience jerky gear shifts, shuddering, making a clunking noise, slipping transmissions, and improper shifting. Other than that, there aren’t many other issues.

But there’s more to it than just that. So today, I’ll be going over all the problems with 6 speed transmission on a 2018 Silverado, how to fix them, the reasons for the problems, and more. Without further ado, let’s begin.

2018 silverado 6 speed transmission problems

What is A 6 Speed Transmission?

The transmission on a vehicle is a part that takes power from the engine and transfers it to your wheels, making them move. It means that a good transmission will be smooth and fast to accelerate, but a faulty one can slow your car down or even bring it to a complete halt.

The “6-speed” in the transmission refers to how many gears it has. So a 10-speed transmission will have 10 gears, while a 6-speed transmission will have 6 gears.

The more gears it has, the smoother it usually is. But they can be harder to control. So even with a good model, you might have problems. A good example is the 2020 Silverado 1500 10-speed transmission problems.

But to keep things simple, a 6-speed transmission from the 2018 Silverado can be great, easy to accelerate, and fast.

2018 Silverado 6 Speed Transmission Problems & Solutions

With the 2018 Silverado, there are 5 major problems you might come across after using it for a while. So here’s a list of the problems as well as how to fix them in short. I’ll cover them in detail later on in the article.

Clunking noiseChange the transmission fluid
Shuddering transmissionReplace or fix the transmission
Jerky gear shiftsReplace the gears or change the transmission fluid
Slipping transmissionsReplace throttle position sensor and tighten the connectivity
Improper shiftingReplace the transmission or the transmission fluid

How To Fix 2018 Silverado 6 Speed Transmission Problems

Now that you have a general idea of the problems and the solutions, here’s a more in-depth look at all the problems and solutions —

Clunking Noise

After using your 6-speed transmission for a while, the most common problem you might have are clunking noises. You usually won’t find these on a brand new Silverado truck, but they’re common in old transmissions.

These sounds are mostly audible when you drive in low gear or downshift from a relatively high speed.


Sadly, there isn’t a reliable way to fix these clunking noises. Most of the time you’ll have to change the transmission entirely. However, changing the transmission fluids can work out for a lot of people, so it’s worth trying.

The clunking noise is usually caused by worn out gears in your transmission, but the fluid is sometimes the reason too. You can easily find the transmission fluid from a nearby automotive store or from Amazon.

Shuddering Transmission

On a 2018 Silverado, the transmission might shudder when it’s cold. This is more common when you’re going uphill.

 It’s usually caused by a power reduction in your Silverado, and it automatically goes away after a while. The power reduction happens when the transmission slips while being cold, losing power.


A shuddering transmission is most common when your transmission itself is faulty. So to fix it, the best way is to simply replace the transmission. You won’t get this issue unless your transmission is old anyway.

Jerky Gear Shift

Generally, gear shifts are supposed to be smooth and fluid. But aside from that, gears should run smoothly too, but after a while, your 2018 Silverado might feel rough to ride on some gears, which some people call “jerky”.

These don’t occur before at least 70,000 miles with your transmission, though. But the gear changes might feel jerky and running on the gears might feel rough after that point.


The cause of a jerky gear shift is the transmission itself, so you should consider changing it. But other than that, changing the transmission fluid is a great idea.

Slipping Transmissions

Your transmission might slip when the accelerator pedal sensor isn’t working due to a faulty throttle position sensor.

The throttle position sensor verifies how far the pedal is pushed to accelerate or decelerate accordingly.


To fix this you simply have to tighten the connectivity from the sensor to the transmission. But other than that, you might need to replace it entirely. It’s relatively cheap and you can get it from Amazon or a store nearby.

DTC codes regarding fuel such as P0172 and P0175 Chevy Silverado can affect this, so check those before buying it.

Improper Shifting

Finally, improper shifting is the last transmission problem you might have on a 2018 6-speed transmission Silverado. Improper shifting refers to any issue with the shifting, such as hard-to-change gears.


Replacing the transmission fluid should usually fix this issue, but you might need to replace the transmission entirely in some cases.

Frequently Asked Questions(FAQs)

Now that you have a good idea of the 2018 Silverado transmission problems, you can check out the most frequently asked questions I get —

How long do transmissions last?

On a Chevy Silverado, transmissions usually last from 150,000 miles to 200,000 miles before having major problems that can make your vehicle unfunctional. You might see fewer major problems before this distance.

How expensive is it to replace a transmission?

Generally, a Chevy Silverado transmission can cost $2000 to $3500. Other parts such as the transmission fluid can cost much less, coming at less than $150 even for the most premium ones.

Can DTC codes cause a broken transmission?

Some DTC codes which cause leaks can lead to a malfunctioning transmission. This is quite rare, though, and it doesn’t occur most of the time.

Is a 10-speed transmission better than a 6-speed transmission?

In terms of statistics, a 10-speed transmission performs better. However, it’s more expensive and more complex to control and use. So a simple 6-speed transmission works fine too.


Hopefully, now you have a good idea about the 2018 Silverado 6 Speed transmission problems. Most of the problems occur after at least 100,000 miles, and changing the transmission fluid can often fix it.

But other than that, you should change the transmission if you see these problems arise. It could lead to an accident sometime, so it’s better to change them beforehand. Cheers!

Hi, this is Johnny Norris grew up in a car-oriented family. I love helping people by solving different problems they face in their Chevy car. Following my suggestions, how-to guides, you can save up on a lot of money that would have been spent on paying a professional.