Choosing The Right Transmission Fluid For TH400- With Its All Other Facts!

By: James Diaz | September 7, 2022

Transmission Fluid For TH400

There are many factors to consider when choosing the right transmission fluid for your TH400. While a variety of fluids are available on the market, not all of them will be suitable for your specific transmission. 

This blog post will discuss the factors you must consider when selecting. I will also provide you with a list of the best transmission fluids for TH400 transmissions. So, if you want to change the fluid in your TH400, keep reading!

What Is A TH400 Transmission?

A TH400 transmission is a 3-speed automatic transmission that was first introduced in 1964. It was developed by General Motors and is used in various GM vehicles. The TH400 is a wide-ratio transmission, meaning it has a wider gear ratio than other transmissions.

TH400 transmission allows more torque to be transferred to the wheels, which benefits drag racing and other high-performance applications. The TH400 is also known for its durability and reliability, making it a popular choice for those who subject their vehicles to heavy use.

What Is A TH400 Transmission?

What Is Transmission Fluid?

Transmission fluid is a lubricant that helps keep your car’s transmission system cool and operating smoothly. Over time, transmission fluid can break down and become less effective at lubricating your transmission.

This can lead to transmission problems, such as gears slipping or not shifting properly. Checking your transmission fluid regularly and changing it when necessary can help prevent these problems.

What Is Transmission Fluid?

Importance Of Choosing The Right Transmission Fluid For TH400

Transmission fluid is one of the most important fluids in your TH400, and choosing the right one for your car is important. Here are a few things to consider when choosing transmission fluid:

Type of transmission fluid

The type of transmission fluid you need depends on the type of transmission in your vehicle. For example, most automatic transmissions require Dexron III or Dexron VI transmission fluid, while manual transmissions typically use gear oil.


The viscosity of the transmission fluid is also important. Viscosity measures a fluid’s thickness, typically expressed in weight (such as 10W-30 or 75W-90). Moreover, the transmission fluids with a higher viscosity rating are typically better for high-performance or heavy-duty applications.

Friction modifiers

Some transmission fluids also contain friction modifiers, which help to reduce wear on the transmission’s internal components. However, too much friction modifier can cause problems, so it’s important to choose a transmission fluid that’s specifically designed for your vehicle.

Check your owner’s manual

Finally, always check your owner’s manual for the specific type of transmission fluid recommended for your car. Using the wrong type of fluid can cause serious damage to your transmission.

Capacity Of TH400 Transmission

The capacity of the TH400 transmission fluid will vary depending on the model and year of your vehicle. However, most vehicles generally require between 3-5 quarts of fluid. Consult your owner’s manual or a certified mechanic to be sure. Overfilling the transmission fluid can cause serious damage to your vehicle, so it is important to be precise.

Effective Transmission Fluid Brands for TH400 Transmissions

  • Valvoline
  • Lucas Oil
  • Royal Purple
  • ATF Type F
  • Mobile

How Many Quarts Does A TH400 Filter Change?

The TH400 transmission filter change should be done every 30,000 miles or so. A good rule of thumb is to change the filter whenever you change the transmission fluid. A new filter will ensure that your transmission fluid is clean and debris-free.

  • To change the filter, you’ll need to drain the transmission fluid.
  • Once the fluid has been drained, remove the old filter and install the new one.
  • Use a new gasket or seal when installing the new filter.
  • Refill the transmission with fresh fluid when the new filter is in place.
  • Be sure to use the correct type of fluid for your transmission.
  • Follow the manufacturer’s recommendations for the amount of fluid to add.

After changing the filter and adding fresh fluid, it’s a good idea to take your vehicle for a test drive. This will help ensure that the transmission is shifting properly.

How Do I Identify A TH400 Transmission?

The most common way to identify a TH400 transmission is by the number of bolts that secure the pan to the main case. There are 16 bolts on a TH400 transmission.

Another way to identify a TH400 is by the shape of the pan. The TH400 has a very shallow and wide pan.

Here are some additional identifying characteristics of the TH400:

  • The case is much longer than it is wide
  • There are only 3 gears
  • The output shaft is splined
  • There is no provision for a speedometer drive gear

When Should You Change The Transmission Fluid Of TH400?

As a general rule, it is recommended that you change the transmission fluid every 50,000 miles. However, if you drive in stop-and-go traffic or other conditions that stress the transmission, you may need to change the fluid more frequently.

Also, if you notice the transmission slipping or shifting erratically, it’s a good idea to have the fluid checked and possibly changed.

Does TH400 Have Overdrive?

The answer is no. The TH400 does not have an overdrive gear. It is a 3-speed automatic transmission that was first introduced in 1964. Also, it is a heavy-duty transmission commonly used in high-powered cars and trucks. It does not have an overdrive gear because it was not designed for fuel economy.

The TH400 was designed for strength and durability. It is a very popular transmission and is still used today in many high-powered cars and trucks. It is not known for its fuel economy but it is a strong and durable transmission.

Overall, the TH400 is a great transmission, but it does not have overdrive gear.

Types Transmission Fluid

There are many different types of transmission fluid, and the type you need will depend on the make and model of your car.

Automatic Transmission Fluid (ATF)

The most common transmission fluid is automatic transmission fluid (ATF). This fluid is used in most modern cars with automatic transmissions.

Manual Transmission Fluid (MTF)

Another type of transmission fluid is manual transmission fluid (MTF). This fluid is used in cars with manual transmissions.

Different ATF and MTF, such as synthetic ATF and conventional ATF. You should check your owner’s manual to see what type of transmission fluid is recommended for your car.

6 Signs Of Faulty Transmission

  1. Check Engine Light is On 

When your vehicle’s check engine light turns on, it’s a good indication that something is wrong with the gearbox. Although there may be other causes, having a professional examine your vehicle to see whether the gearbox is malfunctioning is a good idea.

  1. Transmission Fluid is Leaking 

Transmission fluid often appears crimson and may have leaked beneath your vehicle. The transmission is leaking and needs to be fixed or replaced.

  1. Transmission fluid is Dirty 

A transmission problem may be the cause of filthy transmission fluid. If your transmission fluid isn’t a transparent pink or red tint, you should get your automobile inspected.

  1. Your Car is Slipping 

When shifting gears, if your vehicle seems to be sliding, it indicates a problem with the gearbox. Problems with the clutch or transmission fluid might cause this.

  1. Grinding or Shaking 

Another warning indication of a failing transmission is the presence of grinding or shaking during gear changes. This might be due to some different difficulties, so it’s best to get your automobile looked at thoroughly.

  1. Delay in Shifting 

There may be a problem with your transmission if there is a lag between gear changes. A lack of transmission fluid, a malfunctioning clutch, or something else might be to blame. The sooner your automobile is checked out if you discover this issue, the better.

If you see any of these symptoms, it is highly recommended that you get your vehicle inspected by a qualified mechanic immediately. Transmission issues are usually solvable if discovered early on but may rapidly deteriorate into a far more serious and costly problem if not.

The Bottom Line

The bottom line is that it’s essential to use the correct transmission fluid in your TH400. Using an incorrect or low-quality fluid can cause all sorts of problems, from decreased performance and fuel economy to damage to the transmission itself.

Make sure you consult your vehicle’s owner’s manual to find out which type of transmission fluid is recommended and then stick with that brand and type of fluid. Doing so will help ensure optimal performance and longevity for your TH400 transmission.