7 frequent ways the JD X738 likes to break.. (+ Troubleshooting guide)

The John Deere X738 lawn tractor is a premium offering from John Deere’s revered X-Series, boasting a robust 25.5 horsepower liquid-cooled gasoline engine, with an alternative powerful diesel engine option of 30.2 horsepower. Manufactured at John Deere’s facility in Horicon, Wisconsin, this lawn tractor is designed for a variety of lawn maintenance tasks, offering a hydrostatic transmission for seamless maneuvering and precise control.

The common issues associated range from engine issues, lack of traction, and blade malfunctions, to battery and transmission issues. Addressing these is crucial—whether you’re considering purchasing this model or already own one and are facing some challenges. This model overall has a lot of challenges and we wouldn’t recommend it.

Let’s delve into the most common John Deere X738 issues, understand their root causes, and explore how to troubleshoot them. Igra-World, with its seasoned mechanics boasting years of hands-on experience, has delved deep into customer inquiries, forum discussions, and real-world troubleshooting to compile a comprehensive guide to assist you in keeping your lawn tractor in prime condition.

How to troubleshoot the most common issues:

Engine (severity: high)
How to fix: Check fuel filter and spark plug; if issues persist, consult a professional for potential fuel pump or carburetor defects.

Lack of Traction (severity: medium)
How to fix: Ensure tires are properly inflated; if symptoms persists, inspect the drive belt or drive train.

Blade (severity: medium)
How to fix: Check blade engagement cable and blade switch; consult a professional for potential blade spindle damage.

Battery (severity: medium)
How to fix: Inspect battery terminals and battery condition; consider replacing the battery or checking the alternator.

Transmission (severity: high)
How to fix: Check transmission fluid level and gear condition; consult a professional for transmission servicing.

Deck Belt * (severity: low)
How to fix: Inspect, adjust or replace the deck belt to improve cutting performance.

Hydraulic Leaks* (severity: medium)
How to fix: Inspect hydraulic system for leaks, replace damaged components, and ensure proper installation.

1. Engine

The most common culprits causing engine issues are a clogged fuel filter, a worn-out spark plug, and issues with the fuel system such as incorrect fuel grade or debris in the fuel.

The truck’s Kawasaki 745cc 2-cylinder gasoline engine, with a fuel tank capacity of 5.2 gallons, is prone to issues over time. A clogged fuel filter can starve the engine of fuel, leading to poor performance or even failure to start. Similarly, a worn-out spark plug can cause ignition issues, making it hard to start the engine. Incorrect fuel grade or debris in the fuel system can also lead to engine failures, affecting the tractor’s performance and longevity.

The tractor’s fuel system, including its fuel filter and fuel pump, along with the spark plug, are crucial components that need to be in good working condition to ensure the engine runs smoothly. The electro-hydraulic clutch and hydrostatic transmission, although not directly related to the engine, play a significant role in the overall performance and should be checked if engine problems persist.

How to Fix Engine Issues:

  1. Begin by inspecting the fuel filter for any clogs—replace it if necessary.
  2. Check the spark plug for wear or damage—replace it if it’s worn out.
  3. Ensure you are using the correct grade of fuel for your tractor—refer to the owner’s manual for recommendations.
  4. Inspect the fuel system for any debris or dirt—clean it thoroughly.
  5. If the problem persists, consult a professional mechanic to check for potential issues with the fuel pump or carburetor.

2. Lack of Traction

The most common issues causing a lack of traction are improperly inflated tires, a malfunctioning drive belt, or issues within the drive train.

The John Deere X738, with its robust mechanical design, is engineered to provide a smooth ride across various terrains. However, the tires are the first point of contact with the ground, and their proper inflation is crucial for adequate traction. An underinflated tire can significantly reduce grip, making the tractor slip, especially on slopes. The drive belt is another critical component that transfers power from the engine to the wheels. A worn-out or loose drive belt can lead to insufficient power transmission, causing traction issues.

Moreover, the drive train, which comprises the transmission, differential, and axles, plays a vital role in delivering engine power to the wheels efficiently. Any malfunction within these components can lead to traction issues. The specifications of the John Deere X738, such as its 4-wheel drive and differential lock, are designed to enhance traction but can be compromised if any of the mentioned components are in disrepair.

How to Fix Lack of Traction:

  1. Check the tire pressure: Ensure that all tires are inflated to the recommended pressure as per the user manual.
  2. Inspect the drive belt: Look for signs of wear, tear, or looseness and replace it if necessary.
  3. Examine the drive train: If the problem persists, inspect the drive train for any damages or malfunctions. It might be a good idea to consult a professional mechanic for a thorough examination.

3. Blade Issues

The most common issues causing blade problems are related to the blade engagement cable, blade switch, and potentially the blade spindle which might be damaged.

The blade issues primarily arise from a malfunctioning blade engagement cable, a faulty blade switch, or a damaged blade spindle. The specifications of the X738, such as its 25.5 horsepower liquid-cooled gasoline engine and hydrostatic transmission with infinite forward and reverse speeds, ensure a smooth operation under normal circumstances. However, the blade engagement mechanism is crucial for the mower’s functionality.

A malfunctioning blade engagement cable could lead to the blades not engaging or disengaging properly. Similarly, a faulty blade switch or a damaged blade spindle could halt the blade operation altogether, rendering the mower useless. The electric clutch and the mid PTO (Power Take-off) which are part of the blade engagement mechanism, play a pivotal role in ensuring the blades operate as intended. Any discrepancy in these components could lead to blade problems. The blade issues not only hinder the mowing process but could also be a safety hazard! Hence, addressing these problems promptly is imperative.

How to Fix Blade Issues:

  1. Inspect the blade engagement cable for any disconnections or damages—ensure it is properly connected to the operator’s station.
  2. Check the blade switch for any malfunctions—a replacement might be necessary if it’s faulty.
  3. Examine the blade spindle for any damages—consult a professional for a thorough inspection and repair.
  4. If the blade problems persist, it’s advisable to seek professional help for a comprehensive diagnosis and repair.
  5. Regular maintenance checks—like inspecting the electric clutch and ensuring the mid PTO is functioning correctly—can prevent blade problems in the long run!

4. Battery Issues

The most common issues relating to battery problems are poor connections at the battery terminals, a deteriorating battery condition, or a malfunctioning alternator.

The lawn mower is equipped with a 12-volt battery that energizes the starting system and sustains the electrical system of the machine. The specifications from the tractor data indicate that the electrical system is designed with a regulated charging system with a 20-amp charging capacity. However, like any mower , it can encounter battery issues that could stem from several mechanical components or parts. The connections at the battery terminals could become corroded or loose, impairing the electrical conductivity.

The battery itself could deteriorate over time, especially if it’s old or has been subjected to extreme temperatures. Moreover, the alternator, which is responsible for recharging the battery and supplying electricity to the tractor when the engine is running, could malfunction. The tractor’s performance, particularly its starting ability and electrical features like lights or the ignition system, heavily relies on the battery’s condition and the efficiency of the charging system. Ensuring that these components are in good working order is crucial to prevent interruptions in your work and maintain the tractor’s operational readiness.

How to Fix Battery Issues:

  1. Begin by turning off the tractor and removing the key from the ignition.
  2. Inspect the battery terminals for corrosion or loose connections. Clean the terminals with a wire brush and tighten any loose connections.
  3. Check the battery’s condition using a voltmeter. A fully charged battery should read around 12.6 volts. If it reads lower, consider recharging the battery.
  4. If the battery is old or continues to lose charge quickly, consider replacing it with a new one.
  5. Inspect the alternator for any signs of damage or wear. If you suspect it’s not charging the battery properly, consider having it tested by a professional.
  6. Check the wiring connections between the battery, alternator, and other electrical components for any signs of damage or loose connections, and secure or replace as necessary.
  7. If you’re not comfortable with checking or replacing electrical components, consider consulting a professional mechanic for assistance.
  8. Once you’ve addressed the issue, start the tractor to ensure that the battery issues have been resolved. If the problem persists, seek professional assistance!

5. Transmission Issues

The most common issues causing transmission problems are low transmission fluid levels and worn gears. These problems can manifest as slipping gears or difficulty in shifting.

The machine can encounter transmission issues which could be due to low transmission fluid or worn gears. The transmission of this lawn tractor is hydrostatic, providing a seamless transition between gears which is crucial for the varied tasks it performs. The tractor also features a four-wheel drive and power steering, which are heavily reliant on the transmission’s performance. Any hiccup in the transmission could lead to a lack of control or reduced efficiency in these systems.

Moreover, the tractor’s ability to switch between tasks smoothly, be it mowing, towing, or any other task, is largely dependent on the transmission functioning correctly. This model has an internal wet disc brake system, which, if affected by transmission issues, could lead to safety concerns. The transmission problems, if not addressed promptly, could escalate, affecting other mechanical components and the overall performance of the tractor.

How to Fix Transmission Issues:

  1. Begin by checking the transmission fluid level. If the level is low, top it off with the recommended transmission fluid.
  2. Inspect the gears for any wear or damage. If the gears are worn, they may need to be replaced.
  3. If the issues persist or if you’re unsure about any step, it’s advisable to consult a professional technician for a thorough diagnosis and repair.
  4. Regular maintenance, such as changing the transmission fluid as per the manufacturer’s guidelines, can help prevent transmission issues in the future.

6. Deck Belt Issues

The most common issues relating to deck belt issues are due to a worn or loose belt which can lead to poor cutting performance, and sometimes, unusual noises emanating from the deck area during operation.

The equipment comes with a mid-mount mower deck available in sizes 48″, 54″, and 60″. The deck belt on this mower is crucial for effective grass-cutting. A worn or improperly adjusted belt can lead to poor cutting performance and sometimes loud chatter or other unusual noises from the deck, especially when the mower is operated on uneven terrain or at inappropriate deck heights.

The belt’s tension and condition are vital for the optimal operation of the mower deck. Additionally, the deck’s anti-scalp wheels and the condition of the blade spindles are other mechanical components that could be related to deck belt issues. The deck’s alignment and the condition of other related parts like the idler arm bushing or the quick coupler and its set screws are also crucial for the smooth operation of the deck.

The auto-connect feature, if not functioning correctly, could also contribute to the deck belt issues, as observed in some cases where a misalignment caused noises and vibrations.

How to Fix Deck Belt Issues:

  1. Inspect the Deck Belt: Check the deck belt for wear, tear, or looseness. Ensure it’s properly seated in the pulleys.
  2. Adjust or Replace the Belt: If the belt is loose, adjust the tension. If it’s worn or damaged, replace it with a new one.
  3. Check the Deck Alignment: Ensure the deck is properly aligned and the anti-scalp wheels are set to the correct height to prevent them from digging into the ground.
  4. Inspect the Blade Spindles: Check the blade spindles for any play or damage, which could affect the belt’s operation.
  5. Lubricate Necessary Parts: Lubricate the zerk fittings and other moving parts associated with the deck and belt operation.
  6. Check the Auto-Connect Feature: If your mower has an auto-connect feature, ensure it’s functioning correctly and not causing any misalignment or noises.
  7. Consult a Technician if Necessary: If the issue persists or if you’re unsure about any step, consider consulting a technician or your local John Deere dealer for assistance.

7. Hydraulic Leaks

The most common issues causing hydraulic leaks are damaged or loose hose fittings, a leaking deck lift cylinder, or a faulty bypass valve. These problems often arise due to wear and tear or improper installation of the hydraulic system components.

The lawn tractor comes with a 25.5HP Kawasaki 745cc 2-cyl gasoline engine and a hydrostatic transmission, which includes an electro-hydraulic clutch. The hydraulic system is crucial for various operations, including lifting and lowering the mower deck. A malfunction in this system, such as a hydraulic leak, can significantly impair the tractor’s performance and even cause severe damage over time.

The hydraulic leaks could stem from several mechanical components, including the hose fittings, deck lift cylinder, or the bypass valve. The X738’s four-wheel drive and power steering features are heavily reliant on the hydraulic system, emphasizing the importance of addressing hydraulic leaks promptly. The tractor’s specifications, such as its weight of 958 lbs (434 kg) and dimensions, highlight its compact yet powerful design, making it a reliable machine for residential lawn care tasks, butttt you must ensure prompt repairs, especially when facing issues like hydraulic leaks.

How to Fix Hydraulic Leaks:

  1. Inspect the Hydraulic System: Begin by inspecting the entire hydraulic system for any visible signs of leaks, damage, or loose fittings.
  2. Identify the Leak Source: Localize the leak by checking the hose fittings, deck lift cylinder, and bypass valve. Utilize a flashlight or place a clean piece of cardboard or shop towels to trace the source of the leak.
  3. Tighten Loose Fittings: If you find any loose hose fittings, tighten them securely to prevent any further leakage.
  4. Replace Damaged Components: Replace any damaged or worn-out components such as hoses, seals, or the deck lift cylinder.
  5. Check the Bypass Valve: Ensure the bypass valve is functioning correctly, repair or replace it if necessary.
  6. Clean the Area: Clean the leaked hydraulic fluid from the area to prevent any contamination or slipping hazards.
  7. Test the System: After fixing the issues, test the hydraulic system by operating the mower deck or other hydraulic-dependent functions to ensure the issue is resolved.
  8. Seek Professional Help: If the problem persists or if you are unsure about any step, it’s advisable to consult a professional mechanic or contact a John Deere service center for assistance.

If you don’t already own one, should you buy it?

The X738 is a mixed bag—offering some notable advantages while also coming with a host of issues. Users appreciate its 4-wheel drive feature, providing better traction on challenging terrains—a boon for homeowners with hilly landscapes. The power steering is a hit, making maneuvering less of a chore. However, the engine’s lack of power is a significant drawback, especially given the hefty price tag. Maintenance can be a hassle with hard-to-reach grease fittings and cumbersome engine screen cleaning. The slow reverse speed is a time-waster, and the fuel consumption—about a gallon per hour—is on the higher side, making it less economical for larger lawns or frequent use.

The X748, a close relative, shares a lineage of engine and transmission problems, which might extend to the X738 given their similarities. The commonality of issues like blade malfunctions and hydraulic leaks is concerning, hinting at potential long-term maintenance headaches.

Users also lament about the X738’s high cost, which doesn’t quite match up to the performance and ease of maintenance offered. Alternatives like the Kubota B2400 or Simplicity Prestige might provide better value for money, with fewer reported issues.

In light of these factors, the X738 might not be the best investment unless the 4-wheel drive is a must-have for your lawn terrain. The recurring maintenance issues and high upfront cost make it a less appealing choice for the average homeowner.

Why trust Igra World?

At Igra World, our seasoned editors and hands-on mechanics embarked on a meticulous journey—researching problems and identifying common issues with the John Deere Z445. Analyzing its performance under various conditions, and documenting troubleshooting steps for each identified issue was a priority. Consulting with actual mechanics provided real-world insights while testing proposed solutions ensured accuracy. The process of compiling this guide was exhaustive—reviewing the John Deere Z445 model, comparing it with other models, and evaluating the effectiveness of the solutions provided.

Our verdict: the Z445, though marketed as a reliable model, showcased numerous shortcomings—engine stalling, uneven mowing, and a cumbersome deck belt replacement process. This guide, a testament to our rigorous examination, aims to equip lawn tractor buyers and owners with a candid, professional analysis, ensuring they are well-informed before making a purchase or attempting repairs.

About Jeff Henderson

Have a question regarding your lawn tractor? Igra World writer Jeff Henderson may have covered it already on this site, if not you can contact him at jeff.h@igra-world.com and (417) 414-5099 if you have an problem you can't find an answer to. Jeff is a part time tractor mechanic and landscaping company owner who lives in Springfield, Missouri. He has over 10 years of experience in tractor repair and small engine repair, and has worked with John Deere, Husqvarna, Toro, Troy Bilt, Cub Cadet and Kubota equipment.

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