If you’re a homeowner or landscaping professional, the John Deere D140 can be a reliable lawn tractor for your projects. Regardless of the grass size, this lawn tractor is powerful enough to tackle small- to medium-sized lawns.
And thanks to its reverse mowing technology, it is convenient on terrain with obstacles. Unfortunately, your new JD D140 will likely develop problems over time. The most common John Deere D140 problems are starter issues, excessive vibrations, problematic steering, smoke emission, and hydrostatic transmission issues.
Before you consider taking the lawn tractor to a professional, we want to help you fix these problems. Here’s how to solve JD D140 issues.
John Deere D140 Starter Problems
Does your D140 fail to start after turning the key on? Many users find it hard to determine the cause of starting issues in this lawn tractor.
The starter might be the culprit if the battery is in good condition and all the connections are in place. Sometimes, you might turn the key and hear a clicking noise, but the lawn tractor won’t start. If the mower has a problematic starter, look out for the following:
- Loose or broken starter solenoid connections
- A defective starter
How to fix:
Before fixing issues with the starter, confirm your lawn tractor has a fully-charged battery. You can also check the terminals and cable connectors to ascertain they’re not corroded. After ensuring these components are okay, go on and inspect the starter.
Look for loose connections or burnt/damaged starter solenoid wires. You can disconnect and reconnect the wires. If you find a burnt or broken/frayed wire, replace it.
The problem will persist if the starter is faulty. Start by disconnecting all your mower’s power sources and the spark plug. Next, test the starter with a voltmeter and check if it indicates a voltage. Replace the defective starter if there’s no voltage.
John Deere D140 Steering Problems
Your lawn tractor might be difficult to steer when navigating obstacles. For example, the JD D140 steering might feel stiff or unresponsive over time. Sometimes, the steering wheel might vibrate while riding the lawn tractor.
Below are the common causes of steering issues in D140 lawn tractors:
- Worn bushings that hold the steering gears
- Low lubricant
- Low tire pressure
If you want to avoid John Deere D140 problems related to the steering, always stick to the maintenance schedule. However, if the issues occur, fix them as follows:
How to fix:
The cause of a stiff steering wheel might be a low lubricant. Add grease and test-drive the lawn tractor to see if you’ve resolved the issue.
This problem is also common in other D100 lawn tractor series. If greasing doesn’t solve the problem, check for worn bushings. The bushings are susceptible to wear and may fail to match the steering gears.
When you address the problem earlier, you might only need to replace the bushings. However, if you continue using the mower, you’ll need to replace the bushings and gears.
If steering has excessive vibration, the tire pressure might be low. Inspect the tires and add air pressure as necessary.
Emitting Black Smoke
A JD D140 lawn tractor that emits black smoke while mowing your yard can cause concern. This problem is common with lawn tractors and might occur with excessive use over the years.
So, what might be the problem with your D140? Below are the causative factors of black smoke in your lawn tractor:
- Old or contaminated engine oil
- Clogged air filter
- A partially engaged throttle
How to fix:
If your lawn tractor has old or contaminated engine oil, drain the oil and add a fresh one. You can check the JD D140 manual for the recommended engine oil.
Next, check if the air filter has dirt or oil build-up. Clean the dirt filter or replace it if it looks oily.
Lastly, an idle D140 might continue burning fuel, resulting in black smoke. This problem usually occurs if the lawn tractor has a partially engaged throttle. Adjust and close the choke to ensure you have a fully engaged throttle.
John Deere D140 Transmission Problems
Riding your D140 on hilly or bumpy terrain for an extended period can wreak havoc on its transmission system.
Over time, you might experience John Deere D140 hydrostatic transmission problems with your lawn tractor. When these issues occur, they can significantly affect the lawn tractor’s smooth operations.
As with many John Deere D140 problems, transmission issues might occur after using the lawn tractor for an extended period.
In most cases, transmission problems in this lawn tractor manifest in the following ways:
- Low transmission power
- Leaks from the transmission
- Shifting problems
- Excessive noise from the hydrostatic transmission
How to fix:
The transmission power might be low if your mower struggles to mow uphill. Check if low transmission fluid level is the culprit and add more if necessary.
Transmission fluid lubricates the gears to allow for smooth shifting. The gears might get worn faster if your lawn tractor struggles with low fluid levels. Eventually, you may see leaks from the transmission system. Always check the fluid level and add more if it’s low.
Low fluid viscosity can also cause transmission fluid problems. If the viscosity level is low, the D140 engine will require more power to start and run the engine. Climate changes, such as cold weather, can affect the fluid’s viscosity. Drain the old fluid and add a highly viscous one.
To fix shifting problems in your lawn tractor, check if there’s a worn hydrostatic pump. An authorized dealer or mechanic should help you repair or replace the pump. Next, adjust the shift linkage or replace it if it’s defective.
If the hydrostatic transmission makes excessive noise, a worn or damaged linkage might be the culprit. Hire an experienced mechanic to repair or replace the linkage. You can also add fresh transmission fluid to reduce friction between metals.
Your JD D140 will vibrate to some extent, especially when cutting grass. However, you might notice that the lawn tractor vibrates more than before and causes uneven cuts.
Excessive vibration is another maintenance problem that might leave your lawn tractor in bad shape. The drive belt and cutting blade might be worn, bent, or out of balance. Stop your lawn tractor and look for the following:
- Worn traction and attachment drive belt
- Unbalanced or damaged blade
- Bent blade spindle
How to fix:
Inspect the blade if your lawn tractor vibrates more than usual, resulting in uneven cuts. You can remove the blade to see if it appears unbalanced or damaged. Use a balancer to keep it in position and grind the imbalanced part. If the blade looks damaged beyond repair, replace it.
Inspect the two drive belts and replace them if they have signs of wear or damage.
Lastly, diagnose the blade spindle and check if it appears slightly bent. A bent blade spindle will cause excessive vibration and can damage the blade. If a bent spindle is the culprit, take your lawn tractor to a local repair shop and let a professional repair or replace it.
Are John Deere D140 Problems Deal Breakers?
If you’re a landscaping enthusiast, these issues should not restrain you from owning the D140. This lawn tractor is powerful and durable, provided you take good care of it.
You can keep this lawn tractor in its top condition throughout the years with good maintenance. If you cannot fix any problem with your JD D140, seek help from a dealer or professional mechanic.
Hello! My name is Chris, and I am the founder of Yard Floor. When I was a toddler, my family had a lush green lawn. I was at the center of caring for and maintaining this lawn and even proceeded to take an associate’s Degree in landscaping. I am here to share my years of experience with you – be it repairing your mower/tractor or caring for your lawn.