Cub Cadet Hydrostatic Transmission Problems And Effective Solutions

A cadet hydrostatic transmission has such things as a pump and a motor. And whether you like it or not, they will run into some problems as time goes on.

But before you will begin to panic and make the wrong decision, there are ways you can tackle Cub Cadet hydrostatic transmission problems.

Here in this article, we will talk about the common issues with a cadet hydrostatic transmission and give possible troubleshooting. Keep reading to find the easy way out.

Common Problems Of Cadet Hydrostatic Transmissions

Cub Cadet hydrostatic transmission problems

Before I go any further, have a  look at its common hydrostatic transmission issues:

  • Contamination of air
  • Fluid contamination issue
  • Hydraulic system gets too hot
  • Cold hydraulic system problem
  • System failure

Read this section to learn about the common problems associated with cadet hydrostatic transmission.

  • Air Contamination

About 80% of hydraulic failure in a cadet hydrostatic transmission of Cub Cadet 1050 or other model is caused by air contamination. What this means is this.

When air finds its way into the hydraulic system by a faulty pump or a system breach, the hydraulic fluids become contaminated. Note that, air contamination in a cadet hydrostatic transmission will take place in two ways.

When air enters the system from an external source like a loose connection, it is known as aeration.

Another way air can get into the system is by cavitation, a process by which the pump pulls out and implode the dissolved air in the hydraulic fluid.

Both aeration and cavitation can cause serious damage to your hydrostatic transmission. The solution to air contamination in a cadet hydrostatic transmission is to purge your hydrostatic transmission.

See how to purge a cadet hydrostatic transmission in the troubleshooting section discussed later in this article.

  • Fluid Contamination

This is another common problem in Cub Cadet hydrostatic transmission and just like the air contamination, fluids contamination are caused by leaks in the system.

When your hydraulic fluid is contaminated, the fluid quality is reduced and the system performance is affected.

Also, fluid contamination can cause the system to have temperature issues. For fluid contamination, see how to change hydraulic fluid in the last subheading.

  • Hot Hydraulic System

It is common to hear operators complain about their hydraulic system running too hot for their Cub Cadet SLT1554 or other models. Seriously, it is something to worry about because a hot hydraulic system can prevent lubrication and cause fluids leakage.

Also, it plays a major role in fluids oxidation and thickness. This means that your hydraulic fluid will become thick to allow buildups in the system.

  • Cold Hydraulic System

If your hydraulic system of your Cub Cadet LT1050 or whatever model is too cold, it poses a serious threat to your system. First, the hydraulic fluid becomes thick and unable to reach the pump.

In the long run, the hydraulic system will be unable to dissipate heat and damage the system.

  • System Failure

Some of the things that can cause a system failure in your hydrostatic transmission are dirty cooling fins, faulty components, and incompatible parts.

Due to these above problems, I have recommended this mower brand to avoid in the first place.

Quick Solution For Cub Cadet Zero-Turn Hydrostatic Problems

zero turn hydrostatic problems

Now, we are right here at the spot you’ve probably been waiting for. Here are some DIY troubleshooting tips for your cadet hydrostatic transmissions.

Purge The System

You can consider purging your hydrostatic transmission if your hydraulic motor is way too slow or if you’ve got air trapped in the system. Of course, there are plenty of ways to make your hydrostatic lawnmower faster but how do you purge a Cub Cadet hydrostatic transmission?

Follow the following steps!

  • Park The Machine On A Level Ground

Set the equipment on a flat surface like your car garage and enable the brakes. Ensure that there is enough oil in the system before you begin your troubleshooting.

  • Disassemble The Transmission

Proceed to disengage the system, then sit in the operator’s chair to access and start the engine. While the engine is in motion, move the throttle control in a slow position, detach the brake paddle/clutch, and put the motion control levelers in neutral.

  • Get Rid Of The Air

To do this, you need to push the motion control levelers forward and maintain that position for a minute. Push the motion control levelers backward and maintain another one minute.

Run this a couple of times to let out the air in the hydrostatic transmission.

Clean The Dirty Cooling Fins

Dirty pump cooling fins can cause technical issues in your hydrostatic transmission. What you have to do is to clean off the dirt from the pump cooling fins using a brush or a clean rag. You can also use compressed air for this cleaning operation.

Inspect Damaged Parts And Replace Contaminated Hydraulic Fluids

When you have an overheating hydrostatic transmission, the first thing to do is check the oil level and the heat exchanger. Also, inspect the motor case drain and the pump carefully for excessive bypassing.

Another effective way to deal with cadet hydrostatic transmission is to inspect the system for damaged components and replace them with a new one. Some of the things to check are the connections and the hoses.

Also, you may want to check your steering and hydraulic fluids to see if they are due for replacement. The truth is that overused and old fluids can cause a cadet hydrostatic transmission problem in operation.

Hydraulic fluid will no longer be helpful to a cadet hydrostatic transmission if it has lost its anti-foam additives. Watch this video to solve such transmission problems quickly.

See how to change hydraulic fluid in the section below.

How To Change Hydraulic Fluids In A Cadet Hydrostatic Transmission?

Warm your hydrostatic transmission drive system by driving the machine around for a while. It is to allow every settled contaminant to mix with the fluid and be ready for collection.

Next is to position a container under the oil fill plug at the rear hitch. Take out the drain plug to allow the hydraulic oil to make its way into the container.

Ensure that you clean the sump screen before putting in new hydraulic fluid into the system.

  • Adjust the control rods

Sometimes, a simple adjustment of the control rods is enough to put your cadet hydrostatic transmission in check.

Frequently Asked Questions (FAQs)

Why does my hydrostatic transmission won’t move?

Most probably you did not replace the old hydraulic fluid. Old fluid will lead to premature hydrostatic transmission failure. And that’s why it won’t move.

How do you troubleshoot a hydrostatic transmission?

Check the oil level in the tank if it’s overheating. Check the crossport relief valves and heat exchanger. If you are facing excessive bypassing, check the pump and motor case drains too.

Do hydrostatic transmissions wear out?

Yes, but it takes a long time! If you don’t perform routine maintenance, the hydrostatic transmission will wear out eventually.

Why do hydrostatic transmissions whine?

Making some noise is normal because it’s driving a hydraulic pump! But it sounds whining, there may be air in the drive. Older fluid can be another reason.

What happens if u don’t change transmission fluid?

It will lead to wear and tear on the clutches and other parts of the transmission.


What Cub Cadet hydrostatic transmission problems require is a little troubleshooting here and there. Except for highly technical issues, you can run troubleshooting on your hydrostatic transmission to set it back in motion.

All you need is a little technical know-how and a few tools.

Don’t forget a hydrostatic transmission is what makes your machine helpful and productive. Make sure to put an eye on the system and avoid a last-minute rush for repairs and replacements.

All in all, contact a professional to handle your issues because those machines are your investments.

Good luck.

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