cub cadet rzt 50 transmission problems

How to Fix Cub Cadet RZT 50 Lawn Mower Transmission Problems? [5 Ways to Fix]

Based in Valley City, Ohio, Cub Cadet is a leading name in the mower segment and is also recognized for its legacy in engineering excellence in several other spaces.

The RXT 50 zero-turn mower is perhaps the most solid machine in the company’s lineup and delivers top-notch performance.

However, many users are experiencing issues with the transmission of the Cub Cadet RZT 50 zero-turn mower. Read on to find out key problems with the RZT 50 lawn mower transmission and how to fix the issues.


5 Problems with Cub RZT 50 Zero-Turn Mower Transmission

1. Cub Cadet RZT 50 PTO Clutch Problem

The Cub Cadet RZT 50 mower is equipped with a PTO (power take-off) clutch, which when damaged can affect the mower’s transmission.

There are several ways to identify PTO clutch damage such as when the blades don’t engage when the mower is running.

How to fix Cub Cadet RZT 50 Clutch Problem?

The first thing to do is try and adjust the clutch. Next, check the wiring and if the wiring and the clutch don’t showcase any problem, you may have to replace the clutch.

2. Battery Too Weak

The battery of the Cub Cadet RZT 50 mower gives the electrical and computer systems power internally. Battery connection problems can make the transmission not work consistently or eventually fail.

How to fix Cub Cadet Battery too weak issue?

Remove the battery and clean any dirt and debris accumulated around the electrical connections. Additionally, clean the

Reinstall the battery to see if this fixed the issue. If not, you probably have to replace the battery.

The battery is tucked away neatly under the seat of the Cub Cadet RZT 50 mower so raise the seat to expose the battery compartment.

3. Cub Cadet RZT 50 Transmission Not Generating Enough Power

The Cub Cadet RZT 50 zero-turn mower is fitted with a hydrostatic transmission. When you remove your Cub Cadet RZT 50 mower from storage over the winter, the first thing to do is purge the transmission before use.

Furthermore, it’s worth noting that if your Cub Cadet RZT 50 mower has been serviced recently, you should purge the transmission before you use the mower.

How to fix Cub Cadet RZT 50 mower not generating enough power issue?

  1. Park the Cub Cadet RZT 50 mower on flat ground, engage the parking brake, and put the rear on jack stands.
  2. Top up the oil reservoir according to the specs.
  3. Sit in the seat and start the engine.
  4. Push the motion control levers all the way forward and hold for 5 seconds, after which pull them all the way and hold for 5 seconds.
  5. Repeat step 4 three times to purge the transmission.

4. Sluggish Transmission Performance Caused by Old or Overused Hydraulic Fluids

If the hydraulic fluid shows signs of oxidation, has been overheated or is contaminated, it should be replaced.

The type of hydraulic fluid varies across Cub Cadet mower models, but most models are compatible with 20W-50 motor oil or 15W-50 synthetic motor oil.

It’s fairly easy to change the hydraulic fluid in a Cub Cadet RZT 50 mower. Cub Cadet recommends changing the hydraulic fluid after every 1200 hours of runtime.

However, you should check the level of fluid in the transmission system after every 200 hours of use.

Make sure you use the right hydraulic fluid designed for the Cub Cadet RZT 50 zero-turn mower because using the wrong fluid can cause more harm than good.

How to fix old or overused hydraulic fluid in Cub Cadet RZT 50 zero-turn mower?

You’ll need a few things to change the hydraulic fluid in a Cub Cadet RZT 50 zero-turn mower.

  • Hex set
  • Socket wrench set
  • Strap wrench
  • Fluid catch pan
  • Jack
  • Jack stands
  • Filter
  • Hydraulic fluid
  1. Start by jacking up the rear of the Cub Cadet RZT mower. Try keeping the rear wheels roughly 3 inches off the floor, and then use a pair of jack stands to support the mower.
  2. Under the Cub Cadet RZT 50 mower is a filter guard, which along with the hydro motors needs to be removed.
  3. Locate the filler cap and loosen it and next loosen the vent plug.
  4. Place the catch pan under the fluid drain and remove the drain plug.
  5. Remove the filter, oil the new filter gasket, fill it with new fluid and reinstall the parts.

5. Defective Tensioner Pulley 

The tensioner pulley of the Cub Cadet RZT 50 is designed to help achieve accurate transmission, and maintain the belt’s optimum tension.

When the tensioner pulley fails, it leads to a weak drive belt tension and eventually problems with the hydrostatic transmission of the Cub Cadet RZT 50 mower.

How to fix Cub Cadet RZT 50 defective tensioner pulley?

  1. But the right tensioner pulley for the Cub Cadet RZT 50 mower. Remember, aftermarket parts are cheaper and easily available but it’s best to steer off these as they could be of poor quality.
  2. Remove the defective tensioner that’s located at the right side of the Cub Cadet RZT 50 zero-turn mower and replace it with the new one.

Frequently Asked Questions

How do you fix a weak hydrostatic transmission?

To fix a weak hydrostatic transmission, replace the old hydraulic fluid, remove air from the lines, replace the worn drive belt, and lubricate regularly with quality lubricants.


What causes hydrostatic transmission problems?

There are many causes for hydrostatic transmission problems including a broken hose, clogged filter or failure of any mechanical component.


What transmission does Cub Cadet use?

Cub Cadet mowers are fitted with hydrostatic transmissions.


Final Thoughts

The Cub Cadet RZT 50 is billed as one of the best zero-turn mowers available in the market, but can experience issues especially with the transmission.

I’ve listed 5 common Cub Cadet RZT 50 transmission issues and ways to fix them. If you’re unable to fix the problems, have your looked at by a local official Cub Cadet dealer.