What Type of Transmission Fluid Is Used in a Semi Truck?

May 31, 2022 12:00 am Published by Leave your thoughts

Buying transmission fluid for heavy duty trucks is not always a seamless undertaking. Owners looking for the best transmission fluids for their semi-trucks should understand there are multiple transmission fluids on the market. Here are tips for truck owners to choose the most appropriate transmission fluid. 

OEM Transmission Fluids  

Several fluids are used in semi-trucks depending on the model of the truck and the year it was manufactured. Some of these fluids may include Mercon, Dexron, Power Steering Fluid, ATF+4, and Type F. The latter is no longer used in any car manufactured after 1980.

You should always use the transmission fluid recommended by the manufacturer when your truck is being manufactured. The same case applies when you buy a new transmission for your vehicle. In such an instance, you should buy a new transmission compatible with the fluid that the manufacturer recommended.

Incompatible Transmission Fluids

Buying a transmission fluid that is not compatible with your truck’s transmission can cause serious problems. One of the most common problems is leaks. Incompatible fluids can also lead to transmission failure. Therefore, it is advisable to buy the recommended fluids from the manufacturer.

This type of transmission fluid is used in a semi-truck to help protect the transmission against wear and tear while also providing lubrication. In addition, this fluid is designed to work with the truck’s transmission to provide optimal performance.

What to Look for in Transmission Fluids

It is always essential to look for certain qualities in transmission fluids, regardless of the type of truck you are driving. These qualities include:

New and Fresh

The first thing you should check when buying a new transmission fluid is the date of manufacture. You should only buy fluids that were manufactured recently. This is because transmission fluids tend to go bad over time.

You can tell if fluid is old and no longer effective if it has a dark color. Also, check the expiration date before buying transmission fluids.

Compatible with Your Truck’s Transmission

As mentioned earlier, you should only buy fluids compatible with your truck’s transmission. Incompatible fluids can cause a number of problems, including leaks and transmission failure.

The Right Viscosity

The viscosity of a fluid is important because it determines how well the fluid will flow. If the viscosity is too low or what you expected, the fluid will not be able to provide the necessary lubrication. On the other hand, if the viscosity is too high, the fluid will not flow properly and cause clogs. The best way to determine the right viscosity for your truck’s transmission is to consult the owner’s manual.


Buying the right transmission fluid is important to protect your truck’s transmission. Ensure that the fluid you buy is compatible with your truck’s transmission and has the right viscosity. Also, check the expiration date before purchasing transmission fluids. Reach out to United Diesel Power – Truck Repair Specialist for more tips. 

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