A power takeoff clutch (PTO clutch) is a vital piece of hardware on a tractor or riding lawn mower and, unfortunately, it’s not uncommon that the clutch fails.
The PTO clutch enables the transmission of power created by the engine to other attached equipment such as cutting blades or plows.
If you engage your PTO switch and don’t feel the PTO engage or hear your attachments power up, you may have a bad PTO clutch.
A bad PTO clutch won’t fully power auxiliary attachments to your tractor or mower. A PTO can fail due to excessive heat, bad pulleys, electrical problems, and more.
If you suspect yours has gone bad, here are some common symptoms of Bad PTO clutch to look out for.
Bad PTO Clutch Symptoms
You should avoid operating your PTO clutch until you can diagnose the problem if you hear or notice the following symptoms.
While trying to diagnose the problem, ensure the mower is completely powered off and the ignition key has been removed. You do not want the PTO to engage while you are attempting to troubleshoot it.
PTO Clutch Noisy When Engaged
If when you go to engage your PTO clutch, it makes a lot of unusual noises or sounds like it’s grating against something you should stop what you are doing and turn the machine off.
Check the PTO belt and see if it needs to be replaced. You should replace it if the pulley belt seems worn or is slipping.
Often a noisy PTO clutch means that the clutch bearing has gone bad. If that’s the case, it’s often unserviceable and you’ll have to purchase a new clutch and get it installed.
The Engine Won’t Start
It might seem weird that a bad PTO clutch can affect whether or not the engine can start, but they are often connected.
In some situations, you may have burned the PTO relay or another part of the electrical system linking the PTO to the engine. Check all your connections from the battery, fuses, and relays to ensure everything is working properly.
You should also consider checking some basic parts that would cause the engine to not start like the battery charge, spark plugs or glow plugs, and any possible fuel restrictions in the lines or pump.
Mower Blades Don’t Engage
If your lawn mower blades won’t engage it means the PTO clutch is not getting power or the PTO clutch has fused together due to excessive heat.
This could be caused by a bad fuse which is an easy fix. Just check the fuse and if it’s burnt, replace it with a new one.
If the fuse is okay, your solenoid may not be getting the power it needs to engage. Check the battery voltage on your machine and make sure you’re getting the right numbers.
If you aren’t getting the proper voltage, try purchasing a new battery. If you are getting the right voltage or purchased a new battery, you have a bad solenoid.
A bad solenoid in the PTO clutch is irreparable, so you’ll have to buy a new PTO clutch, unfortunately.
Engine Over Revs When PTO Is Engaged
An engine that has high revs when you engage the PTO clutch means that there is something causing the PTO to draw more power than needed.
This can often be caused by a bad bearing or a bad PTO pulley. As these parts fail, the PTO clutch begins to operate in weird ways and draw more power from the engine.
The Fuse Keeps Blowing
If you noticed that the fuse for your PTO clutch was blown and replaced it only for it to blow again when you attempted to engage the PTO, your PTO is trying to draw too much power.
This can be caused by a seized clutch or an obstruction in the mower blades. Often when cutting grass you can build up debris in the mower deck.
Clear any obstruction once the engine stops and you’ve turned the mower off. If there aren’t any obstructions, the PTO may have seized and will need to be replaced.
Things To Rule Out Before Changing PTO Clutch
Before changing out your PTO clutch and performing some costly repairs, you should check the following parts of the mower.
Battery Voltage
Check that your battery is properly connected and that it has enough voltage. A bad clutch can often be caused by a bad battery.
If your battery doesn’t have enough charge, you should swap it out with a new battery before blaming the PTO clutch.
In-Line Fuse
The fuse for the PTO clutch should be completely intact. Take a look at it and ensure it’s not burnt, blackened, or melted.
A blown fuse is a sign that the PTO tried drawing more power than it should. This is often caused by bad bearings or another mechanical issue.
Replace the fuse if it has blown and try to engage the PTO clutch again. If the in-line fuse blows again, you have a bad PTO clutch and will need to replace it.
Most PTOs use a 10-amp or 15-amp fuse. These are readily available at hardware stores or online.
PTO Switch
The PTO switch activates the clutch for the mower blades or other attachments. When you disengage it, the blades should stop.
If you notice that the blades are either not starting when you engage the switch or they refuse to stop when you disengage it, your PTO switch is not properly connected to your clutch.
There are a number of wires and contact plates between the PTO switch and the clutch itself. Begin looking under the hood and see if you notice any excessive wear, damage, or disconnections along the wiring harness.
Mower Belt In Good Shape
Like all belts on a machine, you should regularly check them and ensure that they’re in good condition and operating properly. The PTO pulley belt is vital for the proper operation of the PTO.
Often a bad PTO clutch can be caused by the belt slipping or a worn belt. Inspect the belt and replace it if needed.
Testing A PTO Clutch
Often the best way to diagnose symptoms of bad PTO clutch is to run through a checklist while trying to operate it.
First, you should check the electric PTO connections and parts. Begin by taking a look at the fuse in the fuse box.
The fuse should be visibly unburnt and in good connection. Replace it if it isn’t.
After looking at the fuses, use a multimeter to check your battery’s voltage. If you aren’t getting the right voltage, you’ll either need to charge your battery up or replace it with a new one.
Once you’ve checked those possible electrical problems, begin turning the mower or tractor on and engaging the PTO.
If you hear the mower blades begin to activate, your solenoid and electrical connections are in proper working order.
With the engine running and the PTO engaged, pay close attention to your RPMs and any noises coming from the PTO.
If your engine starts revving to generate more power for the PTO system or you hear a grinding/squealing noise coming from the PTO, you may have a bad bearing or pulley.
With the engine off and the PTO disengaged, examine the pulley. If the pulley is taut and in good condition, the PTO itself is bad and will need to be replaced or repaired.
Hopefully, you were able to diagnose your symptoms of bad PTO clutch by following this quick rundown or you fixed your problem completely.
How Hard Is It To Change A PTO Clutch Yourself?
The answer to this question depends on your mechanical ability and the tools at hand. PTO clutches can be hard to access depending on your model.
If you are no stranger to operating on heavy machinery and have a garage with the proper tools, you can probably replace your PTO clutch. Ensure the ignition key is removed and everything is fully stopped before you inspect or attempt to repair your PTO clutch.
With that being said, it definitely is easier to simply hand your bad PTO clutch symptoms off to a professional to deal with.
A professional repair shop can easily diagnose and repair any problems you may have. They can often do it quicker than you can at home and you’ll have the peace of mind of knowing that an experienced mechanic has repaired your tractor or mower.
Frequently Asked Questions (FAQ):
Why does my PTO make grinding noises when I engage it?
Your PTO might make grinding noises if the PTO clutch engagement lever is not adjusted correctly. You may also have a bad bearing on the inside of the PTO clutch or the pulley on the PTO may be worn.
With the mower or tractor powered off, check the belt and ensure the lever is set properly.
Can you repair a PTO clutch?
Depending on your model of tractor or mower and the problem, it may be possible to repair the PTO clutch or clutch drive assembly.
Although sometimes, it's better to simply purchase a new PTO clutch and have it installed. If you're having lawn mower clutch problems, bring your mower to a professional for a proper diagnosis.
What causes a PTO clutch to overheat?
PTO clutches often overheat due to bad lubrication, heavy load, or a bad connection.
Check that you do not have too much or too little lubricant, reduce the load you are working with, and ensure that no wires have excessive wear or damage.
What does the PTO clutch do?
The PTO clutch is a vital piece of a lawn tractor or lawn mower. PTO clutches transfer power from the mower engine to auxiliary attachments such as mowing blades, plows, and other attachments that do not generate their own power.
A PTO clutch can engage and disengage these attachments at the push of a button giving you full control over your equipment.
