John Deere 3720 Problems (Get Your Problems Fixed Now)

The 3000 series tractors of John Deere have already earned lots of fame: especially the 3720.

However, along with the capabilities of this tractor, there are some problems as well. These problems are what I will be going through in this guide. 

The John Deere 3720 problems consist of transmission problems, hydraulic problems, engine problems, and fuel problems. Inadequate amounts of fuel/liquid, and damaged components are the main reasons behind the problems. Nevertheless, these can be minimized easily by refilling and replacing the necessary components!  

Along with the problems, you can find detailed solutions to them too. But you have to read this article till the end to do that. Ready to fix your favorite tractor? Read along!

John Deere 3720 Transmission Problems

Problems Reasons Solutions
Jerky clutch response
  • Unadjusted transmission
  • Broken cab mount bolts
  • Calibrate the transmission
  • Replace the cab mount bolts
Slow speed
  • Damaged linkages
  • Broken axle
  • Inadequate amount of transmission fluid
  • Too much weight
  • Repair or replace the linkages
  • Replace the axle
  • Fill up transmission fluid tank
  • Let go of extra weight
Noisy transmission
  • Overloading hydrostatic transmission
  • Insufficient wet disc brake oil
  • Worn-out wheel bearing
  • Damaged transmission components
  • Reduce the load for the transmission
  • Restore the adequate disc brake oil
  • Repair wheel bearings
  • Repair or replace the damaged transmission components

Problem 1: Jerky Clutch Response

This problem is noticeable when the clutch is pressed on the John Deere 3720. The feel of the clutch comes off as jerky. The clutch’s smoothness is improper and it can really throw you off. 


The first reason behind this problem is the unadjusted or uncalibrated transmission of your tractor. It can be thrown off by hitting intense bumps.

The second reason causing this problem can be the broken cab mount bolts of the clutch.


In order for the clutch to perform optimally, the 3720 transmission has to be calibrated. You can use a potentiometer to calibrate the clutch of the 3720.

Also, you have to inspect the cab mount bolts inside the tractor. Broken or damaged cab mount bolts need to be replaced immediately. That way, you can stop the transmission from getting damaged further. 

Problem 2: Slow Speed

A slow John Deere 3720 can be annoying and tough to operate. It can be disadvantageous and John Deere 3720 issues may pop up for this. The issues will most likely occur when you have to climb steep angles.


This problem may happen for 4 reasons. Firstly, the shift linkage may be damaged. Secondly, broken axles may cause this as well.

Thirdly, not enough fuel can cause this problem. Finally, having too much weight on your tractor may steal the tractor’s speed.


To start off, look at your tractor’s linkages (shift linkage, pedal linkage, etc). If the linkages are not adjusted properly, do so. 

If they’re damaged, the linkages can be repaired. Nevertheless, replace the linkages if you can afford them to avoid future problems.

After that, take a look at the axles of the tractor. Having a broken axle is very common in tractors. Since the damaged/broken axles cannot be repaired, you have to replace them.

Then, check the transmission fluid level. If the fluid level is low, fill it up. If there’s too much fuel, you can keep the engine on and burn some of it. Avoid underfilling or overfilling the transmission fluid tank.

At last, see if you’re carrying too much weight. It’s always a good idea to know the weight limitations and specifications.

John Deere 3720

Problem 3: Noisy Transmission

In general, transmissions are supposed to make some noises; when they’re functioning. However, they’re not supposed to be too loud or noisy. That’s when you know something is wrong with the transmission.


4 things can cause a noisy transmission. Firstly, overloading the hydrostatic transmission of the John Deere 3720 can make it noisy. 

Secondly, insufficient wet disc brake oil can create screeching sounds. The excessive friction of the brake discs is the origin of this sound. 

Thirdly, worn-out wheel bearings can be a reason. Finally, damaged transmission components can cause a noisy transmission.


To start off if your transmission is making noise, prevent overloading the tractor. The john deere 3720 lift capacity is 2530 lbs on the back.  

So if you’re putting more weight than 2530 lbs, the transmission will be overloaded.

After that, you will also need to refill the wet disk brake oil. That way, you can avoid the noises and the brakes will perform excellently!

Then, check the wheel bearings of the transmission. Faulty bearings become loose and can make noises when working. Repair the bearings if they are damaged. You can also replace the bearings if they’re far too damaged; it’s inexpensive.

At last, inspect the transmission components thoroughly. If you see any damaged components, try to repair them. If they’re not repairable, replace them.

John Deere 3720 Hydraulic Problems

Problems Reasons Solutions
Low hydropower
  • Hydraulic leaks
  • Worn-out hydraulic filter
  • Replace the hydraulic pipelines 
  • Replace the hydraulic filters
Steering wheel turns too easily
  • Heavily worn-out cylinders and pumps of the steering
  • Low-power steering fluid
  • Worn-out linkages of the steering box, wheel pinion, or rack
  • Replace the steering cylinders and pumps
  • Refill the power steering fluid
  • Replace the linkages

Problem 1: Low Hydropower

If your John Deere 3720 is providing low hydropower, it can be disastrous. You won’t be able to lift heavy elements if this problem occurs. 


Firstly, hydraulic leaks in the hydraulic pipes can be a reason for this problem. The hydraulic system fails to function properly because of the leaks.

Secondly, worn-out filters of the hydraulic system may cause this. Similar to the first reason, it makes the entire hydraulic system partially useless. 


To solve this issue, you need to inspect the hydraulic pipelines. If you see any leaks, you can mitigate this issue by changing the hydraulic pipes. New pipes will allow the fluid to transfer without leakage.

Another thing you have to do is check the hydraulic filters. If the filters are worn out, you got to replace them.

Cleaning the filters is not a good idea in this case. But you can clean it in emergencies to temporarily fix the problem.

Problem 2: Steering Wheel Turns Too Easily

When the hydraulic system isn’t working correctly, the steering wheel can turn easily. This can hinder precision in your tractor driving skills and the tractor’s functionalities. 


The first reason for this problem is the heavily worn-out cylinders and pumps of the steering. They don’t provide enough friction for the steering wheel to turn slowly. 

The second reason causing this issue can be an improper amount of steering fluid. Without the required amount of steering fluid, the hydraulic system under the steering doesn’t work.

Finally, worn-out linkages of the steering box, wheel pinion, or rack may cause this. It makes the entire mechanism wobbly. 


To get rid of this problem, change the steering pumps and cylinders. This way, you can get the hydraulic device for the steering wheel to work well as new. So the steering wheel won’t turn too easily anymore.

Also, you need to refill the power steering fluid. It’s a very important fluid as it can dictate how well your can control your tractor.

At last, have a look at the linkages regarding the steering wheel. Check the steering box linkage, rack linkage, and wheel pinion linkages. If any of them are damaged or too rusty, replace them. 

John Deere 3720 Engine Problems

Problems Reasons Solutions
Engine hard starting
  • Clogged air filter/exhaust pipe
  • Damaged piston rings
  • Restricted fuel lines
  • Replace air filter and clean exhaust pipes
  • Replace the piston rings
  • Clean and wash the fuel lines
Engine overheating
  • Inadequate coolant
  • Clogged radiator
  • Fal belt lose/worn out
  • Provide the required amount of coolant
  • Clean the radiator
  • Replace the fan belt

Problem 1: Engine Hard Starting

When this issue occurs, the engine does hit the ignition but doesn’t start. It can be very frustrating because if you cannot start the John Deere 3720, you can’t work it.


Clogged air filters and exhaust pipes are the main culprits of this issue. If the burnt fuel smoke can’t escape the engine, it won’t start.

Damaged piston rings and restricted fuel lines can also cause this. If the engine doesn’t have enough fuel, the bits of fuel can only go to ignition. It can’t start the tractor.


  • Firstly, you have to replace the air filters in your tractor. Also, clean the exhaust pipes. Create more room for the smoke to extract from the engine.
  • Secondly, you got to check the piston rings. If they’re damaged, they must be replaced with new ones. That way, heat can be transferred the right way.
  • Finally, clean and wash the fuel lines. It’ll lift the restriction alongside any contamination inside it.
John Deere 3720 Engine Hard Starting

Problem 2: Engine Overheating

Overheating issues can cause the 3720’s combustion engine a lot of trouble. Starting from the engine shutting down to thermal damages, it can be dangerous. 


The first reason for an overheating tractor engine is inadequate coolant. Coolant is the main liquid substance to transfer the heat inside the engine. If it’s lower than needed, heat will build up on your tractor’s engine.

The second reason that causes this issue is a clogged radiator. If the radiator fan fails to draw out the hot air from the engine, it can be fatal.

The third and final reason for this problem is a loose or damaged fan belt. The worn-out belt causes the fan to malfunction; hence overheating the engine.


  • To fix this problem, first, provide the required amount of engine coolant to the tractor. Do this at all times; not only when the engine is overheating.
  • Second, you have to clean out the radiator. Take help from this John Deere radiator cleaning guide if you wish.
  • Third, check the fan belt. Generally, fan belts can loosen over a long period of time.  If the fan belt is too loose or damaged, replace it. 

John Deere 3720 Fuel Problems

Problems Reasons Solutions
Diesel motor not turning over
  • Broken or damaged fuel injection pump
  • Incorrect timing for fuel injection pump
  • Replace the fuel injection pump
  • Adjust the timing for the fuel injection pump

Problem 1: Diesel Motor Not Turning over

Usually, the fuel problems are the most common problems of this tractor. If you’re seeing the john deere 3720 error codes, it should be number 69. This code means that there is not enough or no fuel going into the engine. 


If your fuel pumps are broken or damaged, you may face this problem. Also, incorrect timing for the fuel injection pump can sometimes trigger fuel problems. 


First, check the fuel injection pumps. If they’re broken or damaged, replace the fuel pumps with new ones. It will get rid of any fuel-leaking issues as a bonus!

Then, adjust the fuel injection pump timing. That way, you can set the fuel system up to avoid problems!

These problems might have you thinking, is the john deere 3720 a good tractor regarding fuel?

The answer is- yes! The John Deere 3720 is excellent regarding the aspects of fuel. It has great fuel efficiency as well. It has a 5.7L fuel capacity and a direct injection method working for it. However, you have to take care of the tractor in order to avoid fuel problems. 


Is 2000 Hours a Lot on a John Deere Tractor?

No, 2000 hours is not a lot on the John Deere tractor. For tractors, the average hour stands somewhere between 2 – 2.5K. It should be fine in that range. You can put a couple of hours on tractors manufactured by John Deere. However, if the tractor’s not well maintained, even 2000 hours can be too much.

How Many Horsepowers is a John Deere 3720 Tractor?

The John Deere 3720 tractor has a horsepower of 44. The 44 HP provides the tractor with 32.8 kilowatts of energy. Considering that average tractors have around 25-30 horsepower, the 3720 John Deere is terrific.

How Much Does a John Deere 3720 Weigh?

The John Deere 3720 weighs in the range of 2900 – 3570 pounds. It depends on the attachments you have on the tractor. The weight differs based on them. The 3720 weighs maximum when the fuel tank is full.

The Final Words

That’s everything about the john deere 3720 problems. Hopefully, you can solve any issues from now on!

The best way to mitigate tractor issues is to take care of the tractor itself. Keep your tractor clean and replace the filters and fuel regularly.

Also, try to do annual tractor checkups with your trusted mechanic! Best of luck!

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