Learn What Exactly The Allison 1000 Fluid Capacity & Other Facts!

By: James Diaz | August 23, 2022

Allison 1000 Fluid Capacity

Like most people, you don’t know the first thing about your car’s transmission. You may not even know what a transmission is! But read on if you’re curious about car transmissions or want to learn more about your car.

This blog post will discuss the fluid capacity of Allison 1000 and all other facts. So whether you’re simply looking to gain some knowledge or need a fluid change, we’ve got you covered! Let’s get started.

What Is An Allison Transmission?

An Allison transmission is an automatic transmission commonly used in heavy-duty vehicles such as buses and trucks. It is manufactured by the Allison Transmission company, a General Motors subsidiary. 

The Allison transmission is known for its durability and efficiency, and it is often used in applications where heavy loads must be transported over long distances.

The Allison transmission is a hydrokinetic device that uses hydraulic fluid to generate the force needed to move the gears. This type of transmission differs from a traditional automatic transmission, which uses gears to generate the force needed to move the vehicle.

What Is An Allison Transmission

Fluid Capacity Of Allison 1000 Transmission

There are two different Allison 1000 transmissions in operation. One has a little sump pump, while the other has a standard-sized one. The initial fill for the former requires 12.7 quarts, but future fills need just 7.4 quarts. In this case, the former number is 14.8, whereas the latter is 10.6.

This includes 2.4 quarts for the torque converter. This is the basic transmission found in Chevy and GMC 2500HD and 3500HD trucks from 2001 onward, as well as some 1500HD trucks. It is also used in several other GM vehicles, including SUVs and vans.

The Allison 1000 takes six quarts of transmission fluid. You will need to use a synthetic ATF such as Dex/Merc or Mobil 1 synthetic ATF. Please do not use a synthetic blend ATF as it will void the transmission warranty.

Fluid Capacity Of Allison 1000 After Rebuild

The capacity can vary depending on the transmission’s size and the specific fluid type. However, a good rule of thumb is adding about 2-3 quarts of fluid for every 1 gallon of transmission fluid removed during the rebuild process. 

This will ensure that your transmission has the proper amount of fluid and help protect it from damage during operation.

Fluid Capacity Of Allison 1000 After Rebuild

Allison Transmission Fluid Capacity Chart





Transmission Type


Fluid Capacity


1000/2000 Series2001-045-speed16
1000/2000 Series2005-105-speed17.6
3000 Series2004-105-speed17.6
4000 Series2004-075 or 6-speed19.4
4000 Series2008-105 or 6-speed21.1
7000 Series2005-105 or 6-speed21.1

Which Type Of Transmission Fluid Is Perfect For Allison 1000?

Several different transmission fluids can be used in Allison 1000 transmissions, but Dexron III is the most common and recommended type. This fluid is specifically designed for these transmissions and provides the best protection and performance.

Also, two transmission fluids can be used in an Allison 1000 transmission: synthetic and conventional. Synthetic transmission fluid typically offers better performance and protection regarding temperature extremes and overall wear, while conventional transmission fluid is typically less expensive.

Other fluids may also work but may not offer the same level of protection or performance. Always check with your transmission manufacturer or dealer to be sure you are using the recommended fluid for your particular model.

When Should The Allison 1000 Transmission Fluid Be Changed?

The Allison 1000 transmission fluid should be changed every 30,000 miles. If the transmission is used in towing applications or under other strenuous conditions, the fluid should be changed every 15,000 miles.

  • The Allison 1000 transmission does not have a filter, so the fluid does not need to be changed as frequently as it would need to be if the transmission had a filter. 
  • The Allison 1000 transmission is filled with Dexron VI fluid from the factory.
  • If the transmission is being serviced for the first time, or if the fluid has been drained and the transmission has not been serviced in over two years, the fluid should be changed.
  • The Allison 1000 transmission has a self-diagnostic system that can help to identify when the transmission fluid needs to be changed.
  • If the transmission fluid is dark or smells burnt, or the transmission is making noises or shifting improperly, these could also be signs that the transmission fluid needs to be changed.

Cost Of Allison 1000 Transmission Fluid Change

The average cost of an Allison 1000 transmission fluid change is $200. This price can vary depending on your location and the type of vehicle you drive.

If you have a truck with an Allison 1000 transmission, it is recommended that you change the fluid every 50,000 miles. You may be able to get by with changing the fluid every 100,000 miles, but it is best to err on the side of caution.

The Allison 1000 transmission is a workhorse, but it needs to be properly maintained to keep it running smoothly. When changing the fluid, it is important to use the correct fluid type. Allison recommends using synthetic transmission fluid, which can be purchased at most auto parts stores.

Be sure to follow your owner’s manual instructions when changing the fluid, as using the wrong fluid type can damage the transmission.

What Are Signs Of The Bad Transmission Fluid?

The transmission fluid helps keep the car’s transmission cool and lubricated. Over time, the fluid can become contaminated and break down, causing various problems. 

The following signs indicate the transmission fluid may be bad:

  • The car’s transmission feels “slippery.”
  • Shifting gears feels delayed or hesitant.
  • The car’s engine revs, but it doesn’t move as quickly as it should.
  • There is a burning smell coming from the car’s transmission.

If you notice any of these signs, it’s important to take your car to a mechanic and have the transmission fluid checked. If the fluid is bad, it will need to be replaced to avoid further damage to the transmission.

What Happens If You Don’t Change Transmission Fluid?

If you don’t change your transmission fluid, it will eventually become so dirty that it will cause your transmission to malfunction. 

The metal shavings accumulating in the fluid will damage gears and other parts of your transmission. 

Over time, this damage can become so severe that your transmission will need to be replaced.

To avoid this expensive repair, it’s important to change your transmission fluid regularly. Depending on your car, you may need to change it as often as every 30,000 miles. Consult your owner’s manual for specific recommendations.

What’s better between transmission flush and drain?

Flush and drain are two important maintenance procedures for your car’s transmission. But which one is better?

It depends on your car’s individual needs. A flush might be better if your transmission is new or in good condition. This will clean out all the old fluid and debris and replace them with fresh fluid.

However, a drain might be better if your transmission is older or in poor condition. This will remove all the old fluid but won’t replace it with fresh fluid.

This can be a good way to extend the life of your transmission, but it’s important to ensure you keep an eye on the fluid level in your transmission afterward.

Ultimately, it’s important to consult your car’s owner’s manual or a professional mechanic to decide which option is best for your car.

What's better between transmission flush and drain

Allison Transmission Fluid Change Procedure

The process is relatively simple if your Allison transmission is due for a fluid change. It can be done at home with the proper tools and materials. This guide will walk you through the steps necessary to change your Allison transmission fluid.

Before you begin, gather the following materials:

  • Allison Transmission Fluid
  • Funnel
  • Drain pan
  • Ratchet with 8mm socket
  • Ratchet with 10mm socket
  • Ratchet with 13mm socket
  • Extension -Torque wrench

Step 1: 

Park your vehicle on a level surface and set the parking brake. Place the drain pan underneath the transmission fluid drain plug, which is located on the passenger side of the transmission.

Step 2: 

Remove the drain plug with the 8mm socket and ratchet. Allow the fluid to drain completely. Replace the drain plug and tighten it with the ratchet.

Step 3: 

Remove the fill plug on the driver’s side of the transmission. Fill the transmission with new fluid until it drips out of the fill hole. Replace the fill plug and tighten it with the ratchet.

Step 4: 

Start the engine and let it run for a few minutes. With the engine running, shift through the gears and then back to park. Check the fluid level and add more if necessary. 

The process for changing your Allison transmission fluid is now complete. Be sure to dispose of the old fluid properly.

Final Words

The Allison 1000 is a workhorse transmission used in trucks and other vehicles for many years. It is known for its reliability, durability, and high fluid capacity. 

To buy or repair a truck with an Allison 1000 transmission, it is important to know all the facts about this powerful gearbox. This article provides information on the Allison 1000’s fluid capacity and other key specs and features.

This information will be helpful to you whether you are shopping for a new truck or just trying to understand your vehicle better. Thanks for reading!

Video Ref:

  1. https://www.youtube.com/watch?v=N24LFlqpiBo
  2. https://www.youtube.com/watch?v=xeYIaDp4A68
  3. https://www.youtube.com/watch?v=_5PbOg9x4qo