John Deere 7520 Problems (Masterful Troubleshooting Tips)

The reliability of John Deere trucks makes them highly desirable across the globe. However, since it is a vehicle, users often encounter problems.

So, what are some common John Deere 7520 problems?

John  Deere 7520 often struggles with various engine issues like not starting, not rotating, knocking, and overheating. Some transmission issues like the front axle and rear axle making noise also occur in this tractor. There could be steering issues like steering functions poorly and the steering wheel spinning without opposition.   

The purpose of this article is to provide tips on how to troubleshoot and fix some common John Deere 7520 problems. 

John Deere 7520 Engine Problems

Problem  Reason  Solution 
Engine won’t start  Wrong valve timing  Adjust the valve timing 
Worn cylinder bores Rebuild the entire engine
Starter turns bad Repair or replace the starter
Damaged piston rings Replace piston rings
Engine doesn’t rotate Incorrect fuel pump timing  Adjust the timing 
Improper fuel grade Change the fuel
Engine knocks  Lack of oil  Add enough oil
Engine constantly overheats  Lack of coolant in the cooling system  Add enough coolant 
Dirty radiator  Clean the radiator 
Excessive load  Reduce the load
Damaged fan belt Change the fan belt

Problem 1: The engine Won’t Start

Like other John Deere models, failing to start the engine is a common problem with the 7520. When you try to start the vehicle, you may hear a clicking sound or no sound at all if the engine doesn’t start. 

You may also hear the engine crank, but it won’t start. As soon as possible, diagnose the problem in order to fix it.

Reason 1: Wrong Valve Timing 

The leading reason behind this issue is having wrong valve timing. Adjusting the valve timing on an internal combustion engine involves setting the correct timing of the opening and closing of the valves in relation to the position of the pistons in the cylinders. 


It is necessary to adjust the valve timing. By following a few steps, you can adjust the valve timing at home:

  • Idler gear should be completely removed first. On the idler gear, look for the numbers 2,3, and 1.
  • You will now need to attach number 1 of the idler gear to the camshaft and then number 2 as well. 
  • Then, the second idler must be connected to number 3. 

Reason 2: Worn Cylinder Bores  

The second leading cause is that cylinder bores are worn out. A cylinder bore seal prevents combustion chamber gasses and fluids from entering. 

An engine with worn cylinder bores can lose compression, resulting in a loss of power, which ultimately leads to the engine not starting. 


The situation can be handled by rebuilding the entire engine. Reassembling the engine requires disassembling it, replacing or repairing all necessary components, and then reassembling it.

A worn cylinder bore must be repaired or fixed using specialized tools and an understanding of engine repair as it is a complex and technical process. 

Reason 3: Starter Turns Bad

It is likely that a malfunctioning starter is responsible for a diesel engine not starting. Any vehicle must need a good starter to start and run properly. Jumpstarts and tows are required to move a bad starter relay or motor.


First, inspect the starter thoroughly. If you find, the issue can be solved just by repairing it, you can do it by watching this video:

Otherwise, you must install a new starter to fix this issue. 

Reason 4: Damaged Piston Rings

It is also possible that the piston rings are worn or damaged which does not let the engine start. So, look for any damage or fraying.


Replacement of piston rings is necessary to get rid of this situation. It is best to have a professional replace the old part. You may do it on your own if you have sufficient technical knowledge.

Problem 2: Engine Doesn’t Rotate

When the engine of a John Deere 7520 tractor does not rotate, it typically means that there is an issue with the tractor’s starting system. This can happen for a variety of reasons.

Reason 1: Incorrect Fuel Pump Timing

If the fuel pump timing is incorrect, it reduces the engine performance. Also, it can cause engine misfiring along with other obvious issues like excessive smoke production. 


You need to adjust the timing of the fuel pump to get over this situation. You can do it by following the steps below:

  • First, locate the timing mark on the fuel pump drive gear and the camshaft drive gear, or they may be located on other parts of the engine.
  • Now remove the fuel pump timing cover to reach the fuel pump and camshaft drive gears.
  • Then, align the timing marks on the fuel pump drive gear and the camshaft drive gear with the help of the timing light. You may need to loosen the bolts that hold the fuel pump in place and now adjust the fuel pump to the correct position. 

Reason 2: Improper Fuel Grade

Other probable causes include incorrect fuel selection, which results in obstructions of the engine’s rotation. Low-octane fuel could severely damage an engine in a vehicle that requires premium fuel.


To get over this kind of situation, the quality of fuel has to be top-notch. John Deere 7520 has gasoline-powered equipment. 

To ensure that you get the most mileage from your fuel, it is recommended that you use premium gas with 91 octanes. 

Problem 4: Engine Knocks

Engine knocking is another issue users are familiar with. There might be a rattling sound when your car accelerates because air and fuel are ignited prematurely when the engine is compressed.

It’s not a big deal since it can be easily fixed.

Reason: Lack of Oil

The engine is knocking because of oil lacking in the motor. The oil pump cannot circulate enough oil to lubricate all of the moving parts in the engine when the oil pressure is low. 

Due to friction between the engine components, a knocking or ticking noise can occur.   


It is important to regularly check the oil level in your vehicle to avoid this kind of issue. And whenever you find the oil level is low, you must add enough oil.  

Problem 5: Engine Constantly Overheats

Engines built by John Deere 7520 can also suffer from overheating problems. Misfiring will cause heavy damage to the engine. This is why it is essential to pay attention to this issue.

Reason 1: Lack of Coolant in the Cooling System

A lack of coolant in the cooling system is the most common cause of engine overheating. So it is responsible for removing heat from the engine and keeping it at the proper operating temperature.


To solve the issue, coolant must be added to the cooling system in sufficient amounts. Do regularly check the coolant system to reduce any further damage. 

Reason 2: Dirty Radiator

The next possible cause would be a dirty radiator. If the radiator gathers too much dirt, engine overheating is quite common. 


The solution is pretty obvious. You have cleaned the radiator. You can do it very easily by watching the video:

Reason 3: Excessive Load   

Diesel engines can occasionally overheat when loaded with excessive loads. Let’s find a solution to this problem.


Solving the problem is quite simple. You should reduce the load if it’s excessive. Taking the extra load off will prevent the diesel from generating excessive heat. 

Reason 4: Damaged Fan Belt 

Diesel overheating can also be caused by damaged fan belts. Whenever it occurs, try to find a solution as soon as possible.


The repair of damaged fan belts is not possible. It is necessary to replace the fan belt in this case.

Problem 6: Motor Exhaust Excessive White Smoke

When the motor exhaust pipe emits excessive white smoke, try to consider it a problem. When you are going through this situation, you should not drive your car.  


The actual reason is mainly having faulty piston rings. So, your John Deere 7520 motor could produce excessive white smoke if they get damaged.


There is a need to replace the piston rings urgently if white smoke is visible coming from the exhaust pipe. Replacing piston rings requires the expertise of an expert.

John Deere 7520 Transmission Problems

Problem  Reason  Solution 
Front axle making noise  Defective ball bearings  Change the ball bearings 
Gear teeth collapsed  Repair or replace the Gear teeth 
Differential lock brakes  Discs friction clutch worn out  Replace the clutch 
Rear axle making loud noise  Worn or Damaged Bearings Replace the bearing 

Problem 1: Front Axle Making Noise

This tractor has a lot of axle-related issues. A loud knocking noise can be heard coming from the drive axle of your John Deere 7520. You must have faced such a situation if you are a user of 7520. 

Reason 1: Defective Ball Bearing

A defective ball bearing is the most potential cause for making noise in the front axle. Let’s proceed to the solution. 


If ball bearings are damaged, they must be replaced. Attempting to fix the problem yourself won’t work.

Professional guidance is required when replacing ball bearings. Or if you have enough technical knowledge, you can do it yourself.

Reason 2: Gear Teeth Collapsed

Having collapsed gear teeth is another potential reason for the front axle making noise. It can lead your tractor to the drivetrain. 


Gear teeth that collapse usually require repair or replacement. Gear teeth repair is a complex and time-consuming process that requires specialized tools and knowledge of transmissions. 

A trained mechanic or technician should handle this task. However, we recommend you  replace the gear

Problem 2: Differential Locks Break

John Deere 7520 suffers from this problem regularly. It is possible for the tractor to get stuck if the differential lock breaks which can hinder its movement on slippery surfaces.

You shouldn’t run your vehicle in this condition otherwise, it can lead to serious issues. 

Reason: Discs Friction Clutch Worn Out

This is the ultimate leading cause behind differential lock breaking. Besides this issue, worn friction discs in a clutch can cause other problems with the clutch and transmission system.


It is usually necessary to replace a clutch when the friction discs wear out. There is usually a complex and time-consuming process involved in clutch repair, which requires the use of specialized tools.

Problem 3: Rear Axle Making Loud Noise

If you are a user of John Deere 7520, you may be familiar with the loud noise coming from the rear axle housing. This can be a sign that the axle or the components connected to it are damaged. Let’s find out.

Reason: Worn or Damaged Bearings

The bearings in the rear axle are responsible for keeping the axle in place and allowing it to rotate smoothly. If the bearings are worn or damaged, they may produce a loud noise.


If you want to get rid of this irritating situation, you must replace the bearings. If you leave it unreplaced, it can create additional issues with the vehicle. 

John Deere 7520 Steering Issues

Problem  Reason  Solution 
Steering wheel spinning without opposition  Low oil  Add oil 
Damaged steering cylinder  Replace the damaged part
Faulty power steering pump Replace the pump 
Steering functions poorly  Low oil rating  Add enough oil 
Defective power steering pump Replace the steering pump 
Air in the power steering system Release the air from the system

Problem 1: Steering Wheel Spinning without Opposition

Like other models John Deere 7520 also encounters some steering problems. If the steering wheel of a tractor is spinning without opposition, you should take the matter into consideration as early as possible.

Because if your steering doesn’t function properly, you can’t run your vehicle.

Reason 1: Low Oil 

There is a possibility that low oil levels are causing this problem. Identifying and resolving the problem is easy.


Oil should be topped up if the steering wheel spins without opposition since the oil level has fallen.

Reason 2: Damaged Steering Cylinder 

Another underlying reason for easily spinning steering wheels is faulty steering cylinders. This causes a lot of danger. The sooner you deal with that, the better.


The first step to solving this problem is to determine which part of the cylinder is damaged. So inspect the cylinder properly to find out the damaged part. If that part is changed, the entire problem can be resolved.

Reason 3: Faulty Power Steering Pump 

A power steering pump provides power assistance to the steering system. The steering wheel can spin freely if the pump is leaking or damaged, causing it to not be able to provide enough power assistance.


This issue can be resolved by replacing the steering pump. You should consult a professional since changing it is quite complicated.

Problem 2: Steering Functions Poorly

Another steering issue is very common in John Deere 7520 tractors which is steering functions poorly.  You can imagine how difficult it is to control the tractor if the steering functions poorly.  

Reason 1: Low Oil Rating

Low oil levels in the steering system or dirty oil can lead to poor steering function. This can lead to a loss of steering response in your vehicle.


Ensure you’re topping up your oil if you’re experiencing steering issues due to low oil ratings. If the steering system is filled with enough oil, you won’t face anything like that. 

Reason 2: Defective Power Steering Pump

The next leading reason for this problem is having a defective power steering pump. The power steering pump is responsible for providing power assistance to the steering system. 

Hence, if the pump is leaking or malfunctioning, it may not be able to provide enough power assistance to the steering, which can cause poor steering function. 


Replacement of the steering pump is the only way to resolve this issue. Replaced by a professional, the task must be performed correctly.

Reason 3: Air in the Power Steering System

Power steering can function poorly if the air is trapped in the system, which can reduce its effectiveness.


You must release the trapped air inside the steering system to fix this issue. To do that follow the steps below:

Step 1: Make sure the ignition key is turned on “on” and the engine is running.  The steering wheel should be slowly turned from lock to lock a few times. The fluid will be circulated, and trapped air will be released.

Step 2: Check the fluid level again while the engine is running, and top it off if necessary. Make sure the power steering system is functioning properly after you turn off the engine. You should now be able to feel the steering and see no leaks, so the system is balanced.

Step 3: Repeat turning on the wheel again until the steering feels smooth and normal in the case that the system is not fully balanced.

Remember, in some cases, it will be necessary to open the system and let the trapped air out through the hoses and connections in order to release all of the trapped air.


Why does my John Deere 7520 motor seem very hard to start?

This happens for multiple reasons including weak battery, dirty air filter, fuel problems, and spark plug issues. To get over this situation, you need to check the battery first, then, clean the air filter. After that replace the fuel if the problem lies with that. Finally, change the spark plug. 

How much horsepower does a John Deere 7520 have?

The John Deere 7520 has a maximum horsepower rating of 150 HP. An engine powered by a six-cylinder turbo diesel engine makes this tractor powerful enough to handle heavy-duty tasks like plowing, cultivating, and hauling.

What is the life expectancy of a John Deere 7520 tractor?

Usually, a John Deere 7520 tractor has 4000-5000 hours of lifespan.  However, the life expectancy of a John Deere 7520 tractor can vary greatly depending on factors such as how well it has been maintained and how much it has been used. 


John Deere’s 7520 tractor is powerful and reliable, but it may experience problems like any other technical item. 

Every John Deere 7520 problem has been discussed in the article. You can solve the problem by simply going through the article.

However, if you are still having trouble and aren’t sure how to solve it, you should consult a mechanic.

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