There’s not a lot going on in a John Deere Gator transmission, whether it’s a brand new Gator or a much older one. The newer ones use a CVT (Continuously Variable Transmission), while the older ones are closer to what you would consider “standard.” Unfortunately, both are prone to grinding, and we’ll explain why and what to do.
If you have an older Gator that is grinding gears, you should know that it is pretty standard, and those Gators are designed for you to shift fast into forward or reverse. Newer Gators could have a loose belt, the primary clutch is not releasing, or the “clutch” needs to be tuned.
Regardless of the type, the transmission in a Gator is relatively simple, even the newer CVT transmissions. There isn’t a bunch of shifting involved. After all, just forward, reverse, and neutral.
You Can Watch Your Clutch Operate
One way to determine what is going on with your clutch is to lift the trailer up on the back of the Gator and watch the clutch work.
You obviously can’t do that while driving because you would probably end up with more problems than just your clutch if you tried.
You can elevate your tires off the ground and get someone else to sit in the cab and shift back and forth between forward and reverse while you observe the drive belt, the primary drive clutch, and the driven clutch.
As the throttle is opened up, the Gator is shifted into reverse or forward, or it is placed back in neutral, watch the drive belt and how the primary drive clutch acts. It will also help you to lock down the grinding sound.
How Does the Clutch Work in a John Deere Gator?
The simplest way to explain it is to draw a picture in your mind of two pulleys, one larger and one smaller. The primary pulley (clutch) squeezes tighter to grab the belt pulling it and engaging the drive system.
You have a problem if the primary pulley is not contracting enough to grab the drive belt properly. On the other hand, if it is contracting too much, not allowing the blet to fall into the gap, you’ll have higher RPMs and lower RPMs when the opposite happens.
When idling, if your primary clutch does not completely disengage (letting go of the belt), which causes a grinding sound when you engage the drive at low RPMs. If you can physically watch the drive belt in action, you will see whether or not the primary is engaging and disengaging when it’s supposed to.
The system is relatively simple, with only a forward and reverse, so there isn’t much in the way of gears that you have to worry about grinding and coming unmoored or sliding against each other to create metal-on-metal contact when there isn’t supposed to be any.
You can approach this in one of three ways. The first is to buy an entirely new primary clutch and belt. The second is to have your primary clutch tuned, which is often the better and cheaper way to go, especially if your Gator is pretty new.
The third option is to get in there and thoroughly clean and lubricate the primary clutch and the driven clutch next to the transaxle. For extra precaution, you can lubricate the gear slide from the front, under the steering wheel, to the middle, under the seat, to the back, under the trailer.
Replacing the Clutch Entirely
If you are pretty mechanically inclined, you can do this yourself. However, as we mentioned above, this is a simple system, so don’t let the “continuously variable transmission” language fool you into thinking it is enormously complicated.
It does take a bit of trial and error. However, once you get your new, primary clutch installed, you will need to do the lift mentioned above and get someone else to shift back and forth while you watch the clutch engage and disengage.
From there, you can adjust how hard it engages and disengages. For example, in a low gear (Before and right at ignition), your primary clutch should be tight against the belt because it has to grab it to get going.
It should expand out as you open the throttle because it drops the belt to create a smaller wheel, which finishes rotations faster than a larger wheel. Now, if you replace the primary clutch, you may as well replace it all, including a new drive belt.
Tuning the Clutch
Tuning the clutch, or adjusting it so it properly engages and disengages with the drive belt and the driven clutch, is not too difficult, and you don’t have to be a mechanic to get it done correctly.
- Remove the belt cover from the bottom of the Gator
- Clean any debris or dirt in the primary clutch
- Use spray lubricant on the pinpoints on the primary clutch
- Watch the clutch in action to see if it fully withdraws at idle and slides forward when you open the throttle
- Locate the idle adjustment screw on the primary clutch
- Adjust the screw counterclockwise until it is not in contact with the throttle linkage
- Locate the low-speed screw
- Turn it clockwise while the engine is running until you audibly hear the engine rev down
- Turn it counterclockwise until the engine revs up and then back down
These are the only two screws that you need to worry about. With the pinpoints lubricated and the screws adjusted, watch the clutch in operation as someone else sits behind the wheel.
- Have the driver shift into forward
- Have the driver slowly apply pressure to the pedal, opening up the throttle
- The more they open it, applying gas, the clutch should move towards the belt, tightening it
- When they come off of the gas, the clutch should move back away from the belt, allowing it to loosen
- Ensure that it moves back far enough so that it is no longer engaging when it’s at idle
You run into this problem frequently with go-karts. The same principles apply here, and it boils down to how the primary clutch grabs the belt, causing it to slide up (creating a slower rotation) and back down (creating a faster rotation).
Oftentimes, the clutch needs to be adjusted so that it grabs and releases the belt only when it’s supposed to. However, the majority of the time, the belt is not entirely disengaged when idle, which means that the driven clutch (the smaller one in the back) is still engaged when it’s not supposed to be.
This will often cause the grinding sound that you hear when shifting into forward or reverse. It will also cause other symptoms, such as the Gator moving slightly when you are not applying gas, higher or lower RPMs than usual, and slippage when you apply the gas, opening up the throttle.
Believe it or not, this is probably one of the more straightforward fixes on a John Deere Gator. That’s because the powertrain system in a John Deere Gator is so simple.
One of the best ways to avoid this ever happening, to begin with, is to practice preventative maintenance.
Clean your clutch periodically. It’s simple to access and won’t take more than a few minutes to go over it. Then, keep it well lubricated with spray lubrication. Preventative maintenance is the best way to keep your Gator’s CVT operating smoothly and lasting longer.