In this post, we’ll have a look at some common causes if your ATV won’t move forward or backward when you put it in gear. Typical components that may need to be addressed to fix this are:
- Brakes and bearings
- CVT drive belt and clutches
- Gear shift mechanism
- Axles and driveshaft
- Wet clutch system
- Electric shift motor or gear position sensor
Are you able to push the bike when in neutral?
I recommend that you start your troubleshooting by making sure all four wheels on the ATV spin freely and that there’s nothing in the driveline preventing it from moving as normal.
To test this, all you need to do is to put the ATV in neutral (N), leave the parking brake off, and try to push forward or backward it by hand. Some of the larger ATVs can be a bit heavy to push, even for an adult, but on a flat smooth surface like asphalt or concrete, you should be able to make it move.
If the wheels spin freely, you know that the driveline and brakes are fine and that the problem is with your gearbox, transmission, or gear shifting mechanism. You may jump straight down to troubleshooting transmission issues.
If you cannot get the wheels to turn no matter how hard you push, the problem may still be with your transmission or gear shifter. But because it is far easier, you should start by looking into the bike’s driveline, brakes, and bearings to ensure there are no issues there.
Check if the wheel bearings are spinning freely and not seized
Wheel bearings may seize up completely if you let them wear too far before having them replaced.
- Jack the ATV off the ground and put it on jack stands.
- Check each tire for play. You do this by grabbing the top of the tire with one hand and the bottom of the tire with the other. Wiggle back and forth top to bottom.
- If you feel excessive play, your issue may be with your bearing. Worn bearings need to be replaced.
On solid rear axle racing quads, you should also inspect the carrier bearing as they may break and lock up.
Make sure the brakes are not seized
While you have the wheels off the ground, you should also inspect the brakes.
- Make sure the parking brake is disengaged.
- Remove the tire. You should be able to spin the wheel hub by hand. If not, you can try turning the wheel hub by putting a pry bar between two of the wheel lugs.
- Inspect the brakes. Look for corrosion, dirt, or ice.
- If you’ve been riding in wet conditions and it has now gotten cold, they may be frozen solid. A hairdryer will thaw them if needed.
- Riding in mud may pack your brakes with dirt so that they stick. Proper cleaning should fix your issue.
- If your ATV has been sitting for a longer period of time, the brakes may have corroded, preventing them from releasing properly. Corroded brakes can usually be fixed by disassembling, cleaning, and lubing the caliper glide pins and pistons. Service kits that include replacement brake caliper pistons and glide pins are available for most ATVs. In more severe corrosion cases, you may need to replace the complete brake caliper and brake disk for the brakes to disengage properly.
If you still haven’t found a definite indicator that something is wrong with either the wheel hub assembly or brakes, you should isolate them from the rest of the driveline. This way, you don’t waste time troubleshooting parts of the ATV that may be working as normal.
- Disconnect the driveline and try rotating the wheel hub again.
- If the hub is still not moving, you know that something is seized in the hub or brake assembly. Address these areas before moving on to other parts of the bike.
Do you have a stripped or broken driveshaft or axle?
You usually don’t break an axle without noticing. The most common scenario for broken axles is your front axle popping when struggling in a mud hole at full throttle, and the tire suddenly finds traction. “POP,” and the ATV no longer moves.
An axle may strip if it pops out of place. The C-clip that holds it in place may come loose so that the axle starts moving out until just a small portion is still gripping and the splines stip. You will likely hear scraping noises if the axle has been stripped.
When a driveshaft or axle breaks, your bike will no longer pull on the wheel that the stripped or broken axle goes to. The remaining wheels will likely still pull as normal.
When installing bigger tires, you will add more strain on your bike’s driveline. Consider upgrading your axles to heavy-duty aftermarket parts that don’t break as easily.
The drive belt is shredded
The drive belt on CVT transmissions may break due to old age, wear, or misuse. An old belt that is pushed hard may explode in an instant, leaving the bike stranded.
If your bike stopped moving instantly, you should remove the belt cover to inspect the belt. You may find your belt in a thousand pieces or just worn so bad that it is slipping.
Water has gotten into the drive belt housing
If you get water on the drive belt and CVT clutches, it will break the friction that makes your ATV move. The drive belt housing is sealed and should normally protect the drive belt from splashing water.
But if the cover fasteners are not properly tightened or the seal is not in place, it may not be sealed properly. And if you have been riding in deep water, it may enter the belt housing through the belt housing vents.
If you suspect that water in the belt housing is your cause, there is a drain plug at the bottom that will drain any water that has entered.
After you have gotten all of the water out, the bike should start moving again. Go gentle for the first few miles so that the belt and clutches can dry completely before applying too much throttle, or the belt will slip, causing premature wear.
When you get back home, it’s a good idea to remove the belt cover to see if you can find the cause of water entering.
In addition to loose bolts and a seal that has popped out of its place, you should look for damage to the casing itself. It is not unusual that the cover gets damaged by hitting rocks or branches.
Are you sure the bike is fully in gear? Gear shift mechanism issues
See if you can hear or feel if the gears inside the transmission are shifting when you put the AVT in gear. The gear shift indicator may indicate that the bike is in gear even if the internals have not shifted completely.
If the shifter feels loose or not to be shifting all the way, it may need adjusting. Try setting the bike in gear with a bit more firm motion than normal. You can even gently hit the lever to make it “pop” into gear.
Do not use excessive force; you are only trying to find out if it needs a bit of convincing to pop into gear. If this helps, you will likely be able to fix your issue by adjusting the gear linkage.
Also, make sure none of the visible components in the gear shifting mechanism have come loose or are broken. Some ATVs use a plastic clip that sometimes pops off. And where the shifter rods connect to the transmission, you will find a bell crank that is well known to strip or crack.
On manual clutch setups, you need to make sure the clutch cable is adjusted correctly.
If all of the externals seem fine, but you can still not make the ATV shift completely, you may have a bent or broken shift fork, broken drive chain, or stipped pinion inside the transmission.
Before splitting the case, you can try this:
- The engine should be off.
- Remove the belt cover and drive belt.
- Shift the ATV into gear.
- Try turning the secondary clutch by hand.
- The bike should move. If it doesn’t, you likely have a transmission issue and will need to split the case. Do not attempt such a job if you are not confident you are capable. You will need a service manual.
This post goes more in-depth on possible causes when an ATV won’t go into gear or won’t shift gears.
The primary or secondary clutch in the CVT transmission not working properly
If one of the clutches is not working properly, they may not engage to move your ATV forward.
Listen if you hear any abnormal or weird noises from the belt housing area while in gear and applying throttle.
To further investigate, you need to open the belt cover and inspect how the clutches behave. Keep your hands and any loose objects clear of the clutches any time the motor is running.
- Put the bike in neutral.
- Apply some throttle until the clutches speed up.
- The primary (drive) clutch is the one coming from the engine.
- The secondary (driven) clutch is the one coming from the transmission.
- The belt should not turn on idle but should start turning when you apply throttle.
- The clutches behave differently on different types of ATVs:
On belted ATVs that also have a centrifugal wet clutch, none of the dry clutches should spin on idle, even when in gear. When you apply throttle, the wet clutch engages, which engages the primary clutch, that turns the belt which then spins the secondary.
On belted ATVs without a wet clutch, the primary clutch is spinning all the time, while the secondary clutch only spins when throttle is applied. When idling, the belt rests on a bearing on the spinning primary, but as soon as it speeds up, it grabs onto the belt so that it starts turning.
If your ATV does not behave as described above, you may have issues with the clutches that need to be addressed.
Locked up rear differential
Differentials are another possible culprit if your ATV won’t move. A range of things can go wrong, but here are some of the more common:
- There may be debris or metal shavings constricting the gears. Flush all the old fluid out and add new according to spec.
- The mechanism for engaging or disengaging the diff may be broken. Visually inspect and repair if you see any signs of damage.
- Bearings inside the diff may be worn out or sized. It is not uncommon that dirt and water enter the diff, creating perfect corrosion and premature wear conditions.
- The gears inside the diff may be stripped. Listen for grinding noises. Rebuild kits are available for most ATVs. This job requires above-average mechanical skills.
Wet clutch systems, oil-related issues
Some ATVs have internal wet clutches that sit in an oil sump. The same issues listed here also apply to the Hondas with hydrostatic transmissions.
Make sure you are using the right type of oil
Wet clutch systems require that you use a specific type of oil for the clutches to be working properly. If the oil you are using is not wet clutch safe, it will prevent your wet clutch from engaging and prevent your four-wheeler from moving.
Please refer to your service manual to learn what type of oil your ATV needs.
Make sure the oil level is correct
Another common issue that will prevent your wet clutch from working properly is running with too little oil.
Adding oil to the specified level may, in some cases, be enough to bring your ATV back to full working order.
But if you’ve been running too little oil for too long, you may be looking at expensive repairs such as transmission rebuild, oil pump replacement, or at worst case, a complete engine rebuild.
Your service manual will tell you the correct oil level.
Other wet clutch-related issues
Here are a few issues it may be worth looking into if you suspect that your wet clutch is not working properly:
The clutch may not be adjusted correctly
Some, if not all, wet clutches have an adjustment screw for proper alignment. If not adjusted correctly, the clutch pack will stay disengaged all the time. A service manual will tell you where to find it on your ATV.
Many owners report that they find this adjustment screw very hard to move.
The clutch plates may be hung up or jammed
If the adjuster screw is turned too far, it may push the pressure plate back too far, where it may get hung up. Other components like the clutch plates may hang up or somehow get jammed as well.
To find out, you need to remove the clutch plate cover on your wet clutch. Replace the clutch plates if you see any sign of damage.
Electric gear shift motor not engaging completely
On Honda ES models, you may find that the shift motor is not fully shifting the transmission into gear. It may lurch or make a noise as if it is going into gear, but in reality, it bumps back out of gear as soon as you apply throttle.
The grease used inside these motors may be too heavy, or it tends to gum up over time. Cleaning out the old grease and adding white lithium grease may be all that is needed to bring the motor back in working order.
The gear position sensor is bad
Gear position sensors may go bad from shorting out or due to internal corrosion.
If you know your ways around a multimeter, check for continuity in the different gear settings. If there is no continuity in any of the positions, you know that the sensor is toast or needs replacing.