9 John Deere Z445 Mower Problems [Explained]

john deere z445 problems

The John Deere Z445 lawn mower is a zero-turn mower. It’s a powerful unit that has a 24-horsepower capacity engine. This has made it a popular choice for property owners with larger patches of grass or lawn to mow regularly.

Common problems associated with the John Deere Z445 that users have reported include engine problems, issues with the transmission and muffler, and problems with the steering, braking, and cutting deck.

These issues have been more apparent in the newer models produced since 2014. If you own a John Deere Z445 mower, we’ll discuss some of the more common problems and how you can fix them.

Engine Problems

One common problem that users have is that the engine will not start. This can be one of the most challenging problems to diagnose since the engine on this lawn mower is quite complex.

Have a look at the problems mentioned below, as these could be the cause of why you’re having trouble starting your lawn mower, and the fix could be reasonably simple.

Exhaust Problems

When there’s an issue with the exhaust, the exhaust air cannot escape. A clogged-up gas cap vent most likely causes this.


  • The fastest and easiest way to fix this problem is to replace the gas cap vent with a brand-new one.

Transmission Problems

The John Deere Z445 mower uses a hydrostatic transmission. This includes a hydraulic pump that turns electrical power into mechanical power via the hydraulic fluid. This complex system could cause issues with your mower not performing as it should.

That’s why it’s essential to do regular maintenance checks on your mower and to have it serviced at least annually.


  • Always check the oil level and top it up as needed.
  • Change the hydraulic oil, mainly if you haven’t used the mower for some time or notice that the oil has changed viscosity.
  • If your mower has been sitting in the shed for an extended period, you might find air in the pipes. This could reduce the effectiveness of the transmission process. Your owner’s manual should have a section that explains how to remove excess air from inside the pipes.
  • It’s also a good idea to check all of the hydraulic hoses and connections to ensure there are no leakages or any other damage.

Spark Plug Problems

A worn or faulty spark plug could cause all manner of problems with the operation of your mower. One of the primary problems is that your engine won’t start or that it keeps stalling while you’re operating the mower. Thankfully, this is an easy problem to fix.


  • Remove the spark plug from the engine and inspect it to see if it’s worn or covered in dirt and debris. Replace the plug with a new one if necessary.

Safety Problems


For your safety, John Deere has installed several safety switches on its mowers. However, sometimes these can cause problems if they stop functioning correctly. Most often, malfunctioning of the safety switches can cause problems with starting the mower and also the engine stopping suddenly during operation.

  • If the engine stops suddenly or you’re having trouble getting it started, make sure that the mower is not in reverse gear while the cutting deck is engaged.
  • If your mower cuts out while you’re mowing, check that there are no blockages in the cutting deck that would inhibit the normal functioning of the blades.
  • You may also have a more severe problem with wire harness signals or the safety switches themselves. This may need an investigation by a professional mower mechanic to diagnose and fix the issues.

Muffler Problems

On the John Deere Z445 mower, the muffler is quite close to the ground, and this can cause problems, especially with your lawn. You see, the muffler can get quite hot, and if you stop the mower on the lawn after running for a while, it can burn the grass underneath the muffler due to the heat.

There are no real solutions to this problem. All you can do is remember to stop the mower, not while on the lawn, whenever possible.

Steering Problems

When mowing a large lawn area, you need to steer the mower accurately to cover all areas. However, some problems with the steering components on this lawn mower can stop you from doing this.

The two main problems with the steering components are:

  • Only one and not both of the steering arms respond when you turn the wheel.
  • While one steering arm is fine, the other one is quite stiff.


  • Check the steering control rod to see if it’s connected to the motor correctly.
  • Inspect the connections between the engine and the steering arms.
  • Check the bolt that’s situated at the base of the control arm. It might need adjusting.

Cutting Deck Problems

If you constantly try to mow over uneven ground, you might have issues with the cutting deck. The larger 54-inch deck can be challenging to maneuver around trees and other obstacles.

You might also find that you get a relatively uneven cutting performance while you’re going uphill or traversing fairly uneven ground.

Unfortunately, there’s no easy solution to these problems.

Braking Problems

Another common issue reported by John Deere Z445 owners is the inability to brake efficiently or park the mower. To brake, you are required to pull a lever that controls the transmission system to the engine.

Unfortunately, this can easily get jammed up with dirt, debris, and rust. This stops it from working effectively.


  • Clean and lubricate the lever on a very regular basis.
  • For more serious braking problems, take your mower to a professional mechanic to have it checked over.

Frequently Asked Questions:

What engine is in a John Deere Z445?

The John Deere Z445 has a V-Twin 24-horsepower Kawasaki engine.

When should you change the oil in your John Deere mower?

You should change the oil every 500 hours or once a year, whichever comes first.

How often should a John Deere mower be serviced?

It’s recommended that you get your John Deere mower serviced once a year. If you’re mechanically minded, you can even do this yourself with a Home Maintenance Kit.

Final Thoughts

Although the John Deere Z445 is a powerful and popular mower for people with large areas of lawn, it does have some common problems that users have identified.

These include problems with the engine not starting or cutting out, problems with the steering, and also issues with the muffler and the cutting deck. If you service your mower regularly, you should be able to avoid most of these problems, while others can usually be fixed fairly easily.