Fix Husqvarna Lawn Tractor Hydrostatic Transmission Problems

So, you are happy to choose one of the most renowned tractor brands- Husqvarna.

You ordered your tractor, and it arrived in mint condition. You’re on Cloud 9, and the tractor delivers the yard solutions you’ve always craved. But one fine day, your tractor won’t start or is leaking fuel.

What happens next? You could be worrying if you made the right decision while selecting the brand.

We say YES! You made an excellent choice in selecting the Husqvarna lawn tractor. However, the issue may not be with the entire product but a faulty transmission system.

Hydrostatic systems, often known as hydros, hydro-drives, or HSTs on Husqvarna lawn tractors, have varying drives.

Therefore, any component failure can cause hydrostatic transmission problems in them. After all, they are machines, and machines, no matter how good they are, can cause problems at any time.

Husqvarna is a 333-year-old firm known for its cutting-edge technological breakthroughs. The company has established itself alongside competitors like John Deere by providing superior lawnmowers for all mowing demands. So, there is no cause to question the brand’s dependability or quality.

The following are the most prevalent difficulties with Husqvarna lawn tractor hydrostatic transmission:

  1. Hydraulic System Overheating
  2. Transmission Fluid Leakage
  3. Hydrostatic Transmission Pump Failure 
  4. Clogged Filter 
  5. Air in the Line
  6. Cold Hydraulic System
  7. Oil Viscosity

To provide relief, we’ve compiled a list of the top 7 problems your Husqvarna lawn tractor transmission may encounter, along with their solutions.

Continue reading to find out more!

7 Husqvarna Lawn Tractor Hydrostatic Transmission Problems

Husqvarna lawn tractor hydrostatic transmissions are powered primarily by a belt on lawnmowers and a shaft on tractors. Unfortunately, clogged oil filters, leaking fuels, chilly hydraulic systems, and other symptoms indicate that the Husqvarna tractor’s transmission is not working correctly.

But we won’t go through them all at once. Instead, the following subsections will divide the difficulties into separate heads, explore them in-depth, and provide solutions.

1. Hydraulic System Overheating

Hydraulic System Overheating

The pollution of the fluid is one of the most common causes of hydraulic system overheating. Leaks in the system can also contribute to fluid pollution. Many customers have expressed their dissatisfaction with this.

How would you tell if your Husqvarna lawn tractor’s hydraulic system is overheating?

The overheating might not be immediately apparent. Nevertheless, a mistake is visible. The error may not be immediately visible on the screen; a diagnostic tool is needed to obtain these precise error codes. Therefore, careful examination and prompt action are required.

Let the transmission cool down. Check the condition of the gearbox oil after that. You might need to alter it if you discover it to be very thick or jet-black. 

Also, remember to check your clutch to see if that is the cause of the issue. It is best to call for professional help if you are a novice.

2. Transmission Fluid Leakage

Transmission Fluid Leakage

There is no doubt that fuel leaks are one of the most severe hydrostatic transmission issues. This is because, while analyzing the tractor’s issues, several customers complained of a leak in the hydraulic pump’s oil, hampered the mower’s mobility.

So, even though Husqvarna lawn tractors have sophisticated leakage-proof systems, it is common to stumble into a leaking hydrostatic transmission. The oil leakage subsequently leads to the overheating of the transmission.

The following are some of the probable indicators of potential fluid leakage.

  • You will see an error such as P0842
  • Sensors getting a low pressure 
  • There will be a burning smell
  • The tractor won’t run smoothly

The most obvious first step that must be undertaken before the tractor encounters some more serious mechanical troubles is finding the leak’s location and sealing it. To discover if the transmission’s gaskets or seals are worn out, inspect them.

You can also examine the lines for leaks. The best action is to replace the parts if you discover any damage. Another possible culprit is a crankcase that is worn out or has leaks. Again, replace it if that is the case.

Also Read: How to Change a Lawn Mower Fuel Filter? Step By Step Guide

3. Hydrostatic Transmission Pump Failure

Hydrostatic Transmission Pump Failure

We should state upfront that we have no reason to question the dependability of the Husqvarna Transmission Oil Pump. But the fact that the pump is prone to failure is something we cannot overlook.

As we had mentioned, since these are all machines and their parts, problems could arise at any time. The Husqvarna transmission pump is the same.

The pump may struggle to produce pressure quickly after repeated use or lose efficacy early in life. Whatever the reason, the effect would be a reduction in the vehicle’s ability to shift.

If you experience shifting issues when running your tractor, there’s a reasonable probability that the transmission pump is the root of the issue. The worst-case scenario can involve total failure. However, you will mostly notice the shifting problem while driving at the predetermined speed and rpm.

The transmission oil pump replacement is the primary fix for this issue. However, you can also remove the entire pump and rebuild it to correct the problem.

Note: Always turn off the cruise control before shifting.

4. Clogged Filter

Clogged Filter

You may have significant problems if the transmission filter becomes clogged. Maintaining your tractor’s transmission in good functioning order is essential to keeping it running.

The transmission filter’s primary function is to remove particles and muck from the transmission fluid. But regrettably, debris can accumulate in the filter and obstruct fluid movement.

The end effect of this could be an overheated transmission or damage to the transmission’s moving parts. Less lubrication and cooling of the transmission result from less transmission fluid going to it.

Several indications of a blocked filter to look out for include the following. However, this is not an exhaustive list.

  • Leaking transmission
  • Noise 
  • Shifting problems
  • Burning smell
  • Locked reverse gear 
  • Noise in the neutral position, etc.

Most lawn tractors should have their transmission filters changed every 200-300 hours, depending on how they are used or maintained. However, if the problem has already occurred, it is preferable to empty the transmission fluid, put in a new filter, and fill it with the new and fresh transmission fluid. 

We recommend taking your tractor to any Husqvarna authorized dealer to have the transmission filter serviced or replaced.

Also Read: How To Clean A Lawn Mower Air Filter?

5. Air in the Line

This is a consequence of leaving the tractor idle throughout the winter. Air in the lines could develop in an idling tractor. After depleting oil, the air in the line is the most common reason a tractor won’t move.

And even if the lawn tractor manages to move, it would be highly sluggish. This occurs because the tractor lacks sufficient pressure to produce the same outcomes as expected.

So, how to know that there is air in the line? Follow the pointers below and know yourself.

  • The tractor won’t move
  • Even if it moves, it will be very slow
  • Abnormal noise 
  • Overall poor performance of the tractor, etc.

Prevention is always preferable to cure. Therefore, emptying the hydraulic oil from the mower at the end of each season and before storing it for the winter is advisable. This will prevent the buildup of air in the line.

However, proceed as described below if you need to remove air from the line.

  • Lock the lawn tractor’s back wheels.
  • Put the parking brake on.
  • (As directed in the owner’s manual) Disengage the transmission.
  • The lawn tractor should be started and set to neutral.
  • Release the brakes.
  • Reverse the throttle, then hold the position for a further five seconds.
  • Three times, go through this process (forward to backward).

Note: This procedure will aid in clearing the transmission lines of air.

  • Shut off the tractor.
  • Follow the owner’s manual’s instructions to re-engage the transmission.
  • After re-engaging the mower, move it forward for 5 seconds before moving it backward for the same time (repeat this step three times).

6. Cold Hydraulic System

One of the frequent issues with Husqvarna lawn tractors is that they occasionally exhibit a “cold hydraulic system.” too-hot or too-cold hydraulic systems might develop serious issues over time.

We will discuss the cold-running hydraulic system in this section. But if it needs to be identified immediately, it may cause major tractor issues.

The transmission oil thickening is the primary cause of a chilly hydraulic system. The oil that is too thick cannot be pumped. As a result, heat cannot be released from the hydraulic system and harm the gearbox.

It doesn’t take much effort to recognize the symptoms of a cold hydraulic system. Keep an eye on the dashboard’s temperature sensor to detect whether your hydraulic system is getting cold.

Since you already know that thickened oil is the primary cause of a cold hydraulic system, the first fix would be to add some anticoagulant to your transmission fluid. By doing this, the oil would avoid getting too thick.

Nevertheless, some pre-heating might be required if the temperature sensor detects a low temperature. Also, it is best to visit your mechanic if you face this issue frequently.

7. Oil Viscosity

Oil Viscosity

The viscosity of hydraulic oil fluctuates as the ambient temperature changes. There are four levels of oil viscosity: low (up to 35), medium (35-80), high (80-110), and very high (above 110). To simplify, keep in mind that viscosity will rise when it is cold and fall when it is hot.

Both low and high hydraulic oil viscosities will lead to transmission issues, such as damage to the pump, filter, valves, and other components.

If there is an issue with the hydraulic oil viscosity, you may face the following issues.

  • Shifting problems 
  • Abnormal heat generation
  • Overconsumption of energy 
  • Poor air release, etc.

Choosing the correct oil that can function well in any weather is one of the most effective approaches to handling this issue. Additionally, it is occasionally suggested to add fluid viscosity index improvers.

You must also consult the Husqvarna hydrostatic transmission operator manual to solve the viscosity issues. However, if you are having trouble fixing this problem, send your Husqvarna lawn tractor to a certified mechanic.

What is the Average Life of a Husqvarna Lawn Tractor?

A well-known company, Husqvarna competes fiercely with companies like John Deere and Cub Cadet, among others. This brand’s lawn tractors are branded as having an extremely long operating life.

According to our research, you can expect a lifespan of over 400–800 hours. However, we have interviewed customers who confirmed that their Husqvarna tractor lasts more than ten decades.

Isn’t that incredible? The sort of grass you mow, how often you use it, and how routinely you maintain it will all affect how long your tractor will last.

Steps for Regular Maintenance Checks for Your Husqvarna Lawn Tractor Transmission

Dealing with a faulty hydrostatic transmission is frustrating for your wallet and mental state! 

Therefore, performing initial inspections while the system is functioning well is always preferable. 

So, to keep the transmission of your Husqvarna lawn tractor hale and hearty, here are some routine maintenance guidelines you may adhere to.

  • Make sure to drain the oil tank before garaging the tractor. If not, apply oil additives.
  • Check the tank’s fluid levels. Fill it up to the defined level if it displays a low oil level.
  • Verify the hydraulic oil’s color and viscosity to ensure it complies with the User Manual’s requirements.
  • Inline pressure filters should be examined.
  • Verify the control valve’s current and the amplifier’s command voltage.
  • To avoid the buildup of gunk that would cause the air filter to become blocked, make sure to clean the air filter frequently.
  • Check the temperature sensor on the dashboard to determine whether the oil is getting too hot or cold.
  • Look for any leaks in the transmission line, then adjust the connections.
  • At least twice a year, have your Husqvarna lawn tractor inspected and serviced by a licensed Husqvarna dealer.

Why Purge The Hydraulic Drive System Of The Husqvarna Lawn Tractor?

PURGE implies removing or getting rid of something. In this context, it entails removing air from the fluid in the hydrostatic system.

It is critical to do so because if air accumulates in the fluid pump, it will attempt to pressurize air rather than fluid. This is referred to as cavitation. 

This might be troublesome since the transmission cannot exert pressure on the oil for tractor movement. As a response, purging the tractor off the air is vital, especially if it is new or has been stored for an extended period, at least for over 30 days.

Purging is also necessary when the transmission is replaced or removed for servicing. Before reinstalling the transmission and running the tractor, you should purge it.


So that was our take on the Husqvarna lawn tractor transmission and its fixes. We are not disparaging the brand because its tractors occasionally suffer transmission problems. 

However, to ensure a better and problem-free tractor for years, we advise our readers to stay ahead of the curve with their maintenance and servicing requirements. This is crucial since Husqvarna transmission issues typically necessitate a professional inspection, which can take time and be expensive.

We hope that this post was helpful to you. Let us know if you need any further assistance! Also, tell us about your Husqvarna lawn tractors’ performance.


What is the average cost of a Husqvarna lawn tractor?

The average price of a new Husqvarna lawn tractor ranges from $2,000 to over $4,000, depending on the model, features, and other aspects.

What type of oil is used in hydrostatic transmission?

Depending on the tractor model, you can use SAE 20w-50 engine oil in the hydrostatic transmission. Other types of oil are also available, and their use can influence how frequently you need to replace the lubricant and filters. For better and more in-depth information, read the user’s manual.

Note: If your Husqvarna tractor has maintenance-free transmissions, it won’t need routine oil changes unless mentioned in the owner’s manual.

Do I need a professional to solve the Husqvarna lawn tractor transmission problems?

Whether you need to call a professional depends on the problem. However, it is advised to take your Husqvarna lawn tractor for maintenance at least once or twice a year to a local authorized Husqvarna dealer.

How much does a hydrostatic transmission repair cost?

You should budget a minimum of $200 to fix a faulty transmission. The expense, however, depends on how critical the problem is.

Why my Husqvarna lawn tractor engine is running rough?

The throttle cable is to blame if your Husqvarna lawn tractor operates sporadically. If you check it, it might already be broken. The cable needs to be changed to fix the issue. Another reason can be that the clogged carburetor that needs cleaning.

About Jennifer Igra

Growing up in Brooklyn, New York City known for it’s green gardens. Jennifer, a 30 year old gardener and green living fanatic started Igra World to share her gardening journey and increase gardening awareness among masses. Follow Igra World to improve your gardening skills.

Join the discussion