John Deere Z930M Problems and Solutions

The John Deere ZTrak Z930M Zero-Turn mower is well-reviewed and highly recommended by the community. However, many models, especially newer ones, do encounter some mechanical and electric problems. While your Zero Turn mower should last about 2,000 hours before running into a major repair, sometimes they have problems even before the 300 hours of usage. John Deere 930m reviews highlight problems with the switches and ignition power, which is where most issues are likely to come from. 

This guide will cover basic problems and solutions you might encounter early on in usage. However, you can always check the John Deere Z930m manual here for extra information. 

If you’re having problems with your John Deere 930 mower, there are a few basic things that often go wrong. This includes power issues, blade engagement, PTO issues, transmission leaks, and transaxle issues. This troubleshooting guide will help you look at each issue to check for problems with the John Deere Z930M. 

5 Common Issues with the Z930M Lawn Mower 

While there are technically many things that can go wrong with your Z930M lawn mower, the following 5 issues are the most likely. Hopefully this troubleshooting guide helps you identify and resolve those problems. 

1. No Power at Ignition 

If your Z930M isn’t starting it’s probably because of battery power at ignition. Often, the issue relates to the battery, the fuse, or even a bad starter. Here, the fuse is the most likely issue, so it’s a good place to start. If you have a multimeter or a voltmeter, you can also test the battery in a few simple steps. 

Check the Battery 

  • Make sure your multimeter has a DC/A test setting and use it 
  • Set the multimeter to 13 
  • Place the positive lead on the red positive post on the battery 
  • Place the negative lead on the negative pole 
  • Check the power

If your battery has 12.5-12.9, it’s good. If it’s under 10.5, get a new one. On the other hand, if it’s under 12.5, charge it. 

Check the Fuse

  1. Open up the hood.
  2. Look for the fuses, the fuse location is usually in the second coverage casing, next to the diodes. 
  3. Check the main and stator fuses for damage. E.g., are the wires broken, are they black, etc.?
  4. Replace any burnout fuses.

Unfortunately, any burnt fuse is likely because of overpower capacitation. That normally means there’s a short or other overheating problem in the motor. That’s normally caused by broken or bare wires. You can inspect the engine and wires to check for these. You’ll also want to check connections inside switches to be sure. 

2. Mower Blades Keep Turning Off

If your mower blades keep turning off, it usually means the PTO clutch is disengaging. In most cases, that’s caused by problems with the safety switch under the seat. However, you’ll also want to check the battery, in case this is a battery capacitation issue. For example, if the blades switch on and then immediately power down, it might be because they are pulling more power than the battery can supply. Finally, if your mower blades turn on and then stop, it’s likely a belt or PTO clutch issue. In that case, refer to the next section. 

Replace Seat Switch 

  1. Turn the engine off and remove the key from the ignition. 
  2. Flip the seat up.
  3. Check the switch under the seat. Is it loose? Is it broken? If you depress it (while seated on the mower for safety reasons) do the blades turn back on? 
  4. If the switch doesn’t engage the blades when depressed, you may need a new one. However, the new switch on the Z930M is not well-fixed to the seat. This means it easily comes loose, which can cause problems. Re-install it and tighten the switch as firmly as you can against the seat. 
  5. If you have to buy a replacement, it is part AM103119, which normally costs around $15 

Importantly, you should never disable the safety switch in your John Deere. Switches are there to ensure the blades don’t turn on while you aren’t in the seat. This safety mechanism can prevent you from hurting yourself, for example, by accidentally sliding your feet under the deck while the blades are on. 

3. PTO Problems in Z930M 

The PTO clutch controls the movement of the blades. This electromagnetic clutch uses magnetic coil and an actuator. When you supply energy to the PTO clutch using the break switch, the PTO engage lever, and the under-seat switch, the PTO engages. It spins the drive shaft, turning the blades. When you cut power, the actuator is pushed away from the shaft, locking the bar into place. When something goes wrong, the blades either won’t engage or wont’ disengage. However, issues here are very often caused by the switches, the fuse, the solenoid, and the battery. 

  1. Check the switches to ensure they work and are powered. Use a multimeter.
  2. Make sure the engine is off and the key is out. Unplug the positive post from the battery. Check the wires to look for breaks or damage.
  3. Assess the battery power following instructions above. 
  4. Check the belt and belt pulley. If there are breaks, wear, char, or other visible issues, replace the belts. 
  5. Make sure the pulley rotates freely with the PTO disengaged. If not, check for blockage or debris in the pulley motor. 
  6. If it still doesn’t work, remove the clutch using the steps below. 

Replacing the PTO Clutch 

  1. Use a jack or put the tractor up on ramps. 
  2. Engage the brake.
  3. Go through the safety steps of turning off power, removing the key from the ignition, unplugging the positive post from the battery, and then turning the ignition to ensure any residual energy is out of the wires. 
  4. Access the clutch from under the tractor.
  5. Remove the drive belt.
  6. Undo the man power clip.
  7. Remove the center bolt in the pulley. 
  8. Slide the PTO clutch free. This might require some effort as the Z930M uses a 2-stage clutch and the second part is almost always more difficult to remove. 
  9. Test the PTO clutch for resistance. Ideally, it should have 2-4 Ohms of resistance. If not, the clutch is bad 
  10. Check the adjustment to make sure the springs are equally tight on all sides. If the clutch rattles on startup, you probably have to tighten it. 
  11. Check that the clutch actuates if you plug it into a 12v battery. 
  12. If there are problems, you likely want to replace it. 

A new ZTrak Z920M clutch will normally cost $400-$550 depending on location and the retailer. In most cases, you can easily install it yourself. However, if you choose to have a mechanic do the work, you can normally expect $80-$150 extra in labor costs. 

4. Leaking Transmission 

The John Deere 920M uses a Tuff Torg Model TZT-13 series Hydrostatic transaxle transmission. This transmission is prone to leaking. Luckily, this is also normally easy to diagnose. 

Fixing Your Leaking JD 920M Transmission

In almost every case, if your JD hydrostatic transaxle transmission is leaking without other visible damage, it’s the seal under the fan shaft. You also want to replace part #21, as detailed in the manual. As this is a recurring issue, John Deere will normally fix it under warranty and normally by upgrading #21 to a higher quality part, as this is known to fail. Unfortunately, you’ll often need professional repair. If you have the equipment to remove a transmission yourself, you can do so and order the parts from John Deere. However, often, transmissions are too heavy to handle without professional equipment. In most cases, your replacement will take between 4 and 8 hours of work, for $500-$800 in costs. If it’s under warranty, John Deere should cover it for free – so contact your dealer before taking further steps. 

5. Transaxle Issues 

If your John Deere Z930m transmission is being loud, there’s a large chance that there are contaminates in the transmission fluid. Here, the best option is to attempt to troubleshoot and replace the fluid yourself before taking it to a dealer. 

Make sure the engine is off, the key is out of the transmission, and the blades are in “disengages”. Unplug the battery. Make sure you engage the brake. It’s also a good idea to use jacks or a ramp to raise the height of your tractor. This makes it significantly easier to get under the tractor to do the necessary work. That’s especially true if you need an air wrench to remove the caps. 

Replacing the Fluid 

  1. Place drainage pans under both sides of the transmission to catch the drain off
  2. Use a socket wrench to remove the caps on each side of the transmission tanks
  3. Drain the fluid 
  4. Drain the reservoir
  5. Replace the filters 
  6. Replace the fluid and re-fill the reservoir

If there were black chunks or other contaminates in the transmission fluid, you may have found your issue. If not, you may want to start up the machine and check it again. Unfortunately, if you still have issues, you likely have to take it to a professional. Transmissions are heavy, difficult to remove without appropriate power tools, and taking them out without proper tooling and help can be dangerous. Exercise caution if you intend or attempt to do this yourself. 

How Many Hours Do JD Zero Turns Last? 

Your JD Z930M Zero Turn should last at least 2000 hours before running into major mechanical problems. However, this isn’t always the case. For example, many users run into issues very quickly. Depending on when and why issues crop up, they may be covered by your John Deere warranty. 

John Deere Warranty – John Deere offers a 36 month or 1200-hour warranty on all John Deere Z930M tractors. For the first 24 months, there is no hour limitation. This means that if you have issues crop up in the first 300 hours, you should always call your dealer to ask for a fix. During this period, John Deere will repair or replace any part found to be defective in material or workmanship. In this case, you are still responsible for paying service fees and charges. If you’ve made alternations to the machine, your warranty is likely completely void. 

John Deere’s Zero Turns are well liked. However, many people do have issues early on. That’s especially true with the newer models, which very frequently have seat switch issues. Here, the seat switch lacks the stabilizer, so is very prone to coming loose. Luckily, most of these issues are relatively easy to fix on your own, for a low cost. On the other hand, if you have a transmission failure or leakage, contacting the warranty provider for replacement parts can save you several hundred dollars in costs. Unfortunately, you are still responsible for service charges. 


JD Zero turns are one of the most popular riding lawn mowers available. However, there are also plenty of JD Z930M complaints to consider. If you start to experience problems within the first 300 hours, do not hesitate to contact your dealer to ask for a warranty covered fix. However, you should always ask what is covered and if service is covered, because often it is not. In many cases, it’s also relatively easy to check and resolve issues yourself. For example, replacing an under-seat PTO switch can cost as little as $15 + shipping. On the other hand, if you have transmission issues, fixing the problem yourself is often a bad idea. 

Hopefully this overview of common John Deere Z930M issues gives you a good place to start on diagnosing and repairing your own tractor. If you still have questions or want further assistance with the repairs, check our other guides for more help.