John Deere GT235 Problems With Fixes

John Deere has introduced the GT235 as a subcompact tractor for commercial and residential use. Packing a hydrostatic transmission, this popular subcompact lawnmower is perfect for homeowners and farmers. Collectors treasure this model due to its durability and robustness.

The John Deere GT235 is designed to sustain wear and tear over time. Yet, you can experience some issues from time to time. The most common ones include poor engine performance, mower cutting out and turning over hydrostatic transmission issues, and the mower deck not engaging properly.

This article jots down the most common issues that users can experience with John Deere GT235, how to detect them, and quick solutions to fix them.

Common John Deere GT235 Problems & Solutions

Common John Deere GT235 Problems & Solutions
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Having a John Deere GT235 mower can be a lot of fun. Just be aware of the possible problems you can encounter and try taking possible measures to prevent them. So let’s explore the John Deere GT235 issues and learn how to fix them effectively.

1. The Engine is Not Starting

John Deere GT235 owners are likely to face this common issue with the engine. Of course, several factors can be responsible for this commotion. Still, the most likely problem is the ignition system or the fuel-to-air ratio.

However, let’s learn about the factors that can come into play and solutions to fix them.

You might notice that your GT235 mower’s engine is cranking but not starting. Or your engine is cranking and starting but isn’t running smoothly. The possible reasons include contaminated or stale fuel, clogged air or fuel filter, faulty spark plug, or the carburetor not running properly.

How to Fix it?

If you have detected the actual cause behind your engine not starting, try these repairing measures –

  • Firstly, fill up the engine with fresh, quality fuel by replacing the old ones.
  • Next, change the spark plug. However, make sure to install the new spark plug perfectly, keeping a gap of 0.7mm (0.028 inches).
  • Finally, clean the air filter. It shouldn’t be clogged or dirty; otherwise, your engine won’t get enough oxygen. 

2. The Engine is Performing Poorly

The Engine is Performing Poorly
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Poor engine performance is annoying trouble for most John Deere GT235 owners. Although many factors can lead to this issue, dirty fuel is the most common culprit.

You must use clean fuel to power your engine and keep the fuel filters clean. Moreover, if your engine is performing poorly, it indicates engine damage.

How to Fix it?

First, you remove the valve covers and check the push rods. Many users have found the pushing rods entirely deformed and detached from the exhaust valve.

If you encounter the same, try to straighten the rod or change it completely and set the new one in the correct position.

However, remember that cheap ethanol fuel causes a lot of engine problems. First, this poor-quality fuel usually breaks down if it sits too long in the tank. Then, eventually, the valves stick because of a lack of lubrication.

So try always to utilize quality fuel in your GT235 lawnmower. Moreover, if the old gas stays too long between runs, it should be drained and replaced with fresh fuel. Dirty fuel is a leading culprit for engine problems.

3. The Mower Running Poorly at High RPMs

Your John Deere GT235 mower may not run smoothly at high RPMs. You may notice your machine producing a bad smell, the engine overheating, or the engine making a loud knocking sound.

One of the major reasons behind it is mostly damaged brake pads, which are easy to replace and inexpensive. Other factors include belt slipping, clogged gas cap vent, blocked air filter, and air leakage.

How to Fix it?

First, look into the brake pads. If it’s worn, replace them. Next, inspect the belts for any damages. If required, change them.

If all these don’t solve the issue, look into the leaks in the intake manifold. If there is any leak, repair them.

Finally, clean the air filter or replace it if needed. Apart from that, make sure the fuel cap vent is clean so remove debris, if any.

4. Problems with Hydrostatic Transmission

Problems with Hydrostatic Transmission
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John Deere equipped the GT235 model with a hydrostatic transmission. So you fill the transmission system with oil, and the engine pumping action pressurizes it and the wheels get the power from this pressurized oil.

However, the transmission has seals that break down with time, and it eventually causes oil leakage. While the transmission will gradually lose oil, it is likely to fail without sufficient oil.

If oil is leaking from your John Deere GT235, find out the reason behind it and repair it quickly. Moreover, you can even notice the hydrostatic transmission emitting a whining sound loudly. Or your mower isn’t edging forward and reverse.

How to Fix it?

Check whether the transmission fluid is filled to the right level, and then inspect if the transmission is tightly secured to the bracket. They often get loose.

Can you push the mower and the transmission release lever smoothly? If it’s resisting, you can infer where the issue lies.

Bring the manual to know how to bleed the transmission. Another way to fix the problem is by allowing the engine to sit idly, keeping the throttle closed. After that, you open the throttle to see how the engine revs.

Note that if the carburetor is not calibrated, your mower will move slowly. Moreover, try to rotate the transmission belt when the engine is off. Then, you can find out what’s stopping it from moving smoothly.

5. The Deck Isn’t Engaging Properly

The GT235 can engage the mower deck blades with the help of a power take-off clutch. If the blades don’t engage easily, it’s most likely due to a faulty clutch, worn idler pulleys, or bad safety switches.

You will understand that your mower deck isn’t properly engaging by looking at these things –

  • The mower belt area is leaking fluid
  • The mower deck comes loose
  • Blades aren’t moving when it’s on
  • There’s no resistance while the blade is turning.

However, a broken belt tensioner, bad safety switches, maladjusted clutches, or compacted grass beneath the deck might be the reason that the mower deck isn’t engaging appropriately.

How to Fix it?

Follow the below tips to solve any of the causes mentioned above –

  • Change the anti-scalp roller bearings, belt tensioner, and blades.
  • Adjust, replace or repair the power take-off clutch.
  • Clean the deck thoroughly.
  • Inspect the safety switches and adjust their positions or so if needed. Replace them if damaged.

6. The Mower Isn’t Turning Over

The Mower Isn’t Turning Over
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This is another problem you can face with your John Deere GT235 mower. And the most common reason behind it is the battery’s death.

Another reason can be that the starter solenoid is faulty. Well, if the starter solenoid isn’t defective and the battery is even perfect, it can be an electrical issue.

How to Fix it?

So if your mower isn’t turning over, first check whether the connections are tight and the battery is charged.

However, if the problem is in the starter solenoid, you can replace it. You will find this part on the engine’s side.

In case of electrical issues, inspect every fuse. Replace the ones that have blown. All connections must be tight without any dirt or debris on them.

7. Problem in Lowering the 3-Point Hitch

The 3-point hitch is one of the John Deere GT235 mower’s most important parts, supporting several attachments through its lowering function. And you are likely to encounter some glitches over time.

However, every problem with the 3-point hitch won’t seek professional service. You can understand that the 3-point hitch can’t be lowered by noticing the following symptoms –

The rocker switch or control lever is malfunctioning.

The lift arms got stuck in an upward or downward direction and won’t raise or lower.

On the other hand, you can’t lower your mower’s 3-point hitch if there’s a broken cable or chain, a disconnected or faulty wire, a restricted or disconnected line, or a clogged relief valve. The problem can also arise due to inadequate hydraulic fluid circulation throughout the system.

How to Fix it?

Change the hydraulic pump if needed. Next, check the connection between the lift cover switch and the electric clutch wire harness. If the connection is loose, tighten it.

On the other hand, change the defective relay and then look for the defective cables. Replace them if required.

However, if the problem is in the rock shaft control valve, seek professional help for repair.

8. The Battery is Draining Idle

The Battery is Draining Idle
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If your John Deere GT235 is showing this trouble, inspect the battery now, as it’s not receiving sufficient power to function. Eventually, you can suffer from battery short-circuit, and the power will start draining faster. Unfortunately, it can affect the electrical system of your mower, leading to expensive repairs.

So if you notice that the battery isn’t holding a charge or is running down even when not in use, take quick action to fix the battery issue. Many factors are responsible for intermittent battery drainage.

For example, the charging cable needs to be correctly connected, and corroded battery connections or short in the electrical system.

How to Fix it?

Once you detect the cause, you can opt for these fixes –

  • Connect the charging cable again.
  • Check the terminals and replace or clean them if damaged.
  • If the alternator belt is loosened, replace it with a new one.
  • The cables connecting to the battery should be securely attached. If needed, reconnect them.
  • Change the defective battery that even can’t hold a charge any longer.


So these are some of the most common problems you can experience with a John Deere GT235 tractor. However, learning how to fix these issues will keep you away from sudden hassles and expensive repairs.


Can you use John Deere GT235 for mowing hilly terrain?

If properly equipped, you can use the John Deere GT235 to mow hilly terrain. Unfortunately, John Deere didn’t design the machine to tackle inclines or declines. You will have to purchase high-back seats and a differential lock to install them before running this mower in hilly areas.

How long will the John Deere GT235 last?

John Deere GT235 mowers can last you more than 15 years, considering how much it is used, how well you maintain it, and the weather conditions it’s exposed to.

What oil filter and battery size does a John Deere GT235 have?

The John Deere GT235 features the AM107423 oil filter and a 12V 35AH battery.

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.

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