John Deere X350 Problems [3 Common Issues & Solutions!]

The John Deere X350 is a versatile and reliable piece of lawn equipment, but like all machines, it may experience issues over time. This article aims to highlight some of the common problems that X350 owners have reported, particularly focusing on transmission issues, and to offer potential solutions for resolving them.

Problem 1: Mower Loses Power or Acts Like It’s in Neutral


Owners have reported experiencing a sudden loss of power, especially when making tight turns. It appears as though the mower goes into neutral.

Possible Causes and Solutions:

  1. Transaxle Release Lever: Make sure it’s fully pushed in. If the lever is properly engaged and the issue persists, the transaxle might need a rebuild or replacement.
  2. Check for Sliding/Loose Belt and Tensioner: Loose components can also cause a loss of power.
  3. Inspect Engine Pulleys and Transmission End: Make sure there are no damaged or missing keys that could cause the pulleys to disengage.

Problem 2: Unusual Noise and Vibration from the Transmission


Some owners have reported hearing a grinding or growling noise emanating from the rear end, indicating possible gear damage.

Possible Causes and Solutions:

  1. Broken Gear in Transaxle: This will require a new transaxle or an extensive rebuild. Replacements can be expensive, ranging around $700-$932.
  2. Inspect the Driven Pulley: Before replacing the transaxle, check the driven pulley on top of the transmission for any signs of stripping out the spline.
  3. Check Belt Tension and Alignment: A misaligned or loose belt can produce similar noises.

Problem 3: Difficulty in Smooth Operation


Owners have reported that it is hard to operate the mower smoothly, particularly concerning the directional controls, which can engage abruptly.

Possible Causes and Solutions:

  1. Test Under Load: Try driving the tractor while tethered to a stationary object like a tree to simulate a load. This can help in diagnosing the issue.
  2. Check for Wear and Tear: Given the tractor’s age and usage, some parts might be worn out and could require replacement.

Upgrading to a Better Transaxle – The K66Y

If you’re looking to replace the transaxle, the K66Y is often recommended as a superior alternative to the K46 that comes stock with the X350. It is particularly beneficial for those with a lot of hills or more demanding traction needs.


  1. Increased Durability: The K66Y is known for its robustness.
  2. Better Traction: Especially useful for hilly terrains.
  3. DIY-friendly: Most owners with mechanical aptitude find the installation process straightforward.


  1. Cost: It’s more expensive than a direct K46 replacement.
  2. Availability: The K66Y can sometimes be hard to find in stock.
  3. Wheel and Axle Compatibility: You may need to switch to a 5-lug wheel and larger tire setup or adapt the existing ones.

Additional Tips

  • If your tractor is to be used on diverse terrains including hills, side hilling, and rollers, an upgrade to a more durable transaxle is advisable.
  • Always check the entire powertrain, including belts and pulleys, when diagnosing issues.
  • For complex modifications, especially like transaxle replacements, consult professionals or the manufacturer for the best advice.

Frequently Asked Questions:

What is the difference between John Deere X330 and X350?

John Deere X330

  • Engine: Powered by a 20 HP Cyclonic engine.
  • Deck Size: Usually comes with a 42-inch Accel Deep™ Mower Deck.
  • Steering: Manual steering.
  • Transmission: K46 hydrostatic transmission.

John Deere X350

  • Engine: Comes with a more powerful 21.5 HP Kawasaki FS651V engine.
  • Deck Size: More options, including 42-inch and 48-inch Accel Deep™ Mower Decks.
  • Steering: Power steering is available.
  • Transmission: K46 hydrostatic transmission, similar to the X330.

How many belts does a John Deere X350 have?

  1. Drive Belt (Traction Drive Belt): This belt is responsible for transferring power from the engine to the transmission, enabling the machine to move forward and backward. It connects the engine pulley to the transmission pulley.
  2. Mower Deck Belt: This belt transfers power from the engine to the blades on the mower deck, allowing the blades to rotate and cut grass.

The drive belt and the mower deck belt are essential for the proper functioning of the tractor. If either belt becomes worn out or breaks, it will need to be replaced to ensure the tractor continues to operate as intended.


While the John Deere X350 is generally reliable, being aware of these common problems and their solutions can save you time and money. Always consult your owner’s manual or a professional for the most accurate and personalized advice.