All There’s to Know About AX5 Transmission Fluid

Whether you are performing regular maintenance or experiencing any issues with gear shifts there’s a lot to learn about transmission fluid. 

Well, then the question rises about the best choice of AX5 transmission fluid, which one is it? 

75W-90 gear oil with API specification of GL-3 or Gl-4 is the best choice of transmission fluid for AX5 transmission. The Viscosity of this fluid is suitable for cold and hot temperatures. Moreover, it offers excellent oxidation resistance, proper lubrication, and shear stability. 

Wanna know more about the transmission fluid? Well then let’s hop on to details right away-

What Kind of Fluid is Used in AX5 Transmission?

AX5 transmission is a manual transmission commonly found in Jeep vehicles like Jeep Cherokee and Jeep Wrangler models. 75W-90 gear oil with API specification of GL-3 or Gl-4 is normally used for this transmission.

But before you go ahead and buy this fluid from your hardware store here are a few things you should know and go through-

Fluid Capacity:

The total amount of fluid that a particular component or system can hold is the fluid capacity of that component or system. Manual Transmission such as the AX5 usually has a capacity of approximately 2 to 3.5 quarts (2.0 to 3.1 liters).

But for transmission fluid capacity is the amount of fluid needed for proper lubrication and operation of the transmission. This capacity might vary depending on your vehicle. Check your owner’s manual to see the accurate capacity information for your vehicle.


Viscosity determines a fluid’s resistance to flow under certain pressure. This property of transmission fluid affects its ability to lubricate and protect the internal components of the transmission.

75W-90 GL3 or GL4 fluid is specified using the SAE(Society of Automotive Engineers) viscosity classification. “75W” indicates the rating of the fluid during the startup of the vehicle or at colder temperatures.

The ‘W’ stands for winter and 75 represents the fluid’s winter viscosity rating. It means that this fluid has a really low viscosity when it’s at a cold temperature. This allows smoother shifting during cold starts or when you just start the engine. Without fluid with such viscosity, it will be harder for transmission to shift into overdrive.

The number “90” represents the fluid’s kinematic viscosity at 100 °C. It means how the fluid will react when the transmission is under load and heat is being produced.

With a high number of 90 this transmission fluid ensures higher viscosity and better protection under higher temperature conditions.

API Specifications:

Specifications such as API are the industry standard that helps to define the quality and performance required from petroleum products. This ensures the compatibility of the product and its performance.

75W-90 GL-3 transmission fluids GL-3 part indicates the API specification. This GL-3 fluid usually has moderate EP(Extreme Pressure) properties. So, it’s mostly used in a transmission that doesn’t require enhanced EP protection.

GL-4 on the other hand comes with higher EP and more protection against gear wear. So this is best for transmission with higher loads and severe operating conditions. GL-4 is also used as a Jeep transfer case fluid.

Both of these will be good for AX5 transmission but some prefer GL-4 over the other one. But at the end of the day, it depends on what is required by your specific model of vehicle.

Synthetic or Conventional Fluid:

Synthetic fluid provides more improved lubrication and enhances thermal stability. It also offers higher resistance to oxidation and breakdown under high temperatures. 

As a result, it has a smoother cold start, longer lifespans, and extended drain intervals. But it’s on the costlier side.

Conventional fluid on the other hand has lower thermal stability and a shorter lifespan with a more affordable price tag.

Between synthetic and conventional, synthetic fluid is a better choice for AX5 transmission. It will ensure better performance and longevity. But your manufacturer’s label might suggest otherwise so it’s best to check beforehand.

75W-90 GL-3 or Gl-4 usually comes in synthetic formulations. But there are some conventional fluids that meet the 75W-90  viscosity grade and GL-3 or Gl-4 specifications.

Performance Enhancement:

The condition of the transmission, specific vehicle application, and quality of the fluid used determine how much the performance will be enhanced. With a suitable transmission fluid like 75W-90, you can expect smoother gear shifts, reduced gear clash, and overall improved shifting performance.

Moreover, the lubricating properties and additives in the fluid will ensure the minimization of wear on the gears, synchronizers, bearings, and other moving parts. This will prolong their lifespan and promote a smoother operation.

Although the transmission fluid will enhance the performance, this overall improvement is mostly dependent on proper maintenance.


AX5 transmission fluid’s price can vary a lot depending on the brand, the type of fluid, and the location as well. Moreover, the packaging size such as whether you are buying a quart or gallon will also affect the price.

Valvoline Full Synthetic Gear Oil
Source: Amazon

As of 16th May 2023, the price of 1 QT (quart) Valvoline SynPower SAE 75W-90 Full Synthetic Gear Oil is $12.21. This can be different in your particular location. And for other brands, the price can be slightly more or less. But for 1 QT is usually between $8 to $20.

How Often Should You Change AX5 Transmission Fluid?

The exact time to change the AX5 transmission fluid might vary depending on the type of transmission, the use of your vehicle, and the type of fluid you use. But most manufacturers recommend changing the fluid every 30,000 to 60,000 miles for manual transmission.

If you are not sure about the mileage (bought an old car), you can look for these signs, which indicate that your vehicle needs a fluid change-

  • Unexpectedly going forward or backward
  • Difficulty while shifting
  • Excessive grinding noise while shifting
  • Gears slipping 

How to Change the Transmission Fluid?

This is something you can do at home easily. But if you are not used to doing these then it’s best to leave these changes to professionals. With that being said here are the tools you will be needing for the process-

1. Torque Wrench

2. Ratchet Set

3. Plastic Scraper

4. Abrasive Pad for Gasket

5. Brake Cleaner

6. Funnel

7. Safety Goggles

8. Paper Towel

9. Gloves

10. Container to store old fluid

11. Ramp or Jack Stand

With the tools gathered now let’s move on to the steps-

Step 1: Raise the Vehicle Using the Ramp or Jack Stand

First, you need to elevate your vehicle with a Jack stand or ramp to reach the transmission pan. Take the ramp or Jack stand and use it to slowly elevate your vehicle. Next, look for the transmission pan which is usually located near the catalytic converter.

Ramp or Jack Stand
Source: Vehicle Scene

Put the container underneath the transmission pan. There will be multiple bolts securing the pan to its place.

Take the rear ones out first, this way the pan will hang at an angle. This makes it easier to drain the fluid. Once the fluid is completely drained use the ratchet to remove the rest of the bolts.

Step 2: Replace the Fluid Filter

Once the transmission pan is removed, you need to move on to the filter. This filter is normally bolted by one screw. This can be easily removed with a ratchet.

Before putting the filter on, take some transmission fluid and lube up the O-ring. After that, now put the new filter on and bolt the screw back in.

Step 3: Replace the Gasket of the Transmission Pan

Use the Plastic scrapper to remove the rubber gasket from the edge of the pan. Once the gasket is off, use the brake cleaner and paper towel to clean the area. Make sure there’s no brake cleaner left on the edge of the pan. Once it’s dry apply the grease and then put on the new gasket. 

Step 4: Install the Transmission Pan

Put the Transmission pan back into its place by screwing the bolts. Make sure each screw is finger-tight. Don’t tighten them too hard or you may damage your pan. 12 pounds per foot should be the maximum torque used in the case of each bolt.

Step 5: Refill the Transmission Fluid

Look for the Transmission fluid dipstick near the engine bay and remove it. Use the funnel to pour the recommended amount of transmission fluid into the dipstick tube. Once you pour enough amount of fluid, replace the dipstick.

Step 6: Start the Engine & Check for leaks

Now start the vehicle’s engine and let it idle for a couple of minutes. Look for any sign of abnormality. After 5-10 minutes, shut off the engine and check the fluid level. You can add more fluid if it’s necessary.

Here is a video guide; 

Tip: usually when the transmission fluid is low the dashboard will flash a warning light or an indicator will be shown. From there you can easily refill the fluid. But if you are not sure what the indicator light means you can always check your owner’s manual for signs or codes like jeep code u1411.

Frequently Asked Questions (FAQs):

What is the AX5 transmission gear ratio?

AX5 transmission has gear ratios of 1.44,1.00,3.92,0.85, 2.33, and 4.74, 1st through reverse, respectively. The length of the AX5 transmission case is 15-5/8″. It has a mid-plate made of cast iron and a cast aluminum case. The shifter is located in the back quadrant of the assembly and the case is ribbed. 

Is it Okay to Replace AX5 with AX15?

Yes, you can replace the AX5 transmission with the AX15 transmission. This replacement will give you more drivetrain strength. Moreover for power increases such as going from 4 cylinders to a larger V8 or V6, this is actually the ideal transmission. 

What Kind of Oil Should I Use in A 5-speed Manual Transmission?

It is generally advised to use SAE 80W, 75W-90, 80W-90, and SAE 90 manual transmission fluid formulations. Certain situations could call for multi-grade engine oil or automatic transmission fluid. However, manual transmission fluid, on the other hand, is typically the finest choice for manual transmissions.

End Words

That concludes our discussion on AX5 transmission fluid. Before refilling or changing your transmission fluid make sure to check your manufacturer’s guidelines to ensure the transmission’s optimal performance.

Don’t hesitate to ask for help from professionals because working with transmission fluid can be potentially hazardous.

Until next time!

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *