John Deere 4066r Problems

Among most mowers, the John Deere 4066r seems to be a top pick between landscapers and gardeners for its class. Even though a John Deere 4066r’s popularity has to do with its features and powerful engine, it can even run into a problem.

No machine is not bound to have a problem. Any product with mechanical parts will fail in the future with overuse and time. A John Deere 4066r is no apart.

This is why this article will look at some common John Deere 4066r problems, including stalling and engine oil issues which can be annoying for you and its operator.

Sometimes the problem can occur in the PTO system of your John Deere 4066r that needs quick fixes. Therefore let’s uncover those John Deere 4066r problems and how you can solve them with full clarification.

John Deere 4066r Problems

John Deere 4066r Transmission Problems

Transmission Is Excessively Noisy

Your John Deere 4066r transmission will make extreme noise if the gears are defective. Make sure that the backlash is proper. If there are any faulty gears or improper backlash, replace them properly. Sometimes, the problem can be as simple as a worn-out or bent gear shift that needs to be replaced. If you know shift forks are in bad condition, please return them too.

In most cases l, bearings tend to be worn out, which causes extreme noise in transmission. I don’t mind l, replacing it, either. Lastly, check and refill the dance mission fluid with the recommended one with the proper viscosity.

Difficult to shift gears

Problem Solution
Worn out gear shift linkage.  If the gear shift linkage is corroded or deteriorated, replace it with the new one.
Faulty clutch.  Any faulty clutch should be replaced immediately.
Worn out gear shifting mechanism. If the gear system mechanism seems to deteriorate, don’t mind preparing it. If it is in deplorable condition, replace it entirely.
Misadjusted clutch.  If the clutch is not adjusted correctly, you will have difficulty changing or shifting gears. Make sure to adjust appropriately according to the user manual.
Bent gear shift fork. If the gear shift fork is bent, replace it. The same to do if it has wear and tear.

Insufficient Transmission Oil Pressure

Problem Solution
Low Transmission oil level. Fill the transmission housing to the proper oil level. 
Clogged transmission oil filter if this is the case, clean it thoroughly. Doesn’t mind replacing the oil filter if it is poorly damaged.
Worn out gear shifting mechanism. If the gear system mechanism seems to be deteriorated, don’t mind preparing it. If it is in very poor condition, replace it entirely.
Stuck relief valve. If the relief valve is stuck, change it.

Transmission Fluid Leaks

Any fluid leaking from your John Deere 4066r transmission system can be due to a damaged gasket or seal. Therefore, please replace them. Another cause of fluid leakage could be a high fluid level that needs correction. He doesn’t mind draining it. 

John Deere 4066r Regen Problems

Failed Injector: if the Injector of your John Deere 4066r is faulty, the fuel will not flow into the exhaust steam to increase the temperature and start the DPF regen process. Therefore, immediately replace any defective or failed Injector to raise the temperature and start your John Deere 4066r. When there is any problem with a John Deere 4066r engine, you must first look at the failed Injector.

This Injector injects the fuel into the exhaust stream to increase the temperature to start the DPF regeneration process. A failed injector will not allow the system to increase temperatures and is usually one of the first things to check. 

Failed DPF Pressure Sensor

The DPF pressure is responsible for determining the pressure within its filter. Any damage to the pressure sensor will give you an incorrect measurement of the soot level and will fail to select the pressure drop within the DPF filter.

With a failed DPF pressure sensor, you will likely get false readings and experience excessive regens because it cannot sense the pressure between the DPF filter to notify the engine control unit. If you notice your John Deere 4066r DPF readings showing high pressure when it’s not, replace the entire sensor.

Clogged DPF filter

If the DPF filter gets clogged with any foreign object, it will not get enough temperature to burn the soot off. There can be many symptoms of Clogged DPF filters, like prolonged and excessive regions lasting more than an hour. When doing a forced regen, monitor the pressure to ensure everything works correctly and in range. It is essential to either repair a clogged DPF filter or replace it entirely.

Faulty temperature sensors

If the temperature sensor is fixed, it will give you a good reading of how the DPF system operates. It will, in turn, also affect the regen process and stop it. Therefore, replace any 40 temperature sensors.

VGT turbo operation

If the VGT turbo operation is not functioning correctly for your John Deere 4066r regeneration process to start, there will not be enough heat to keep the regens from failing. Users have frequently reported DPF failures due to faulty turbos.

Engine Fault Codes

If the engine fault code is damaged, the regen process will not start. All the engine fault codes that are related to the temperature, emission, pressure, VGT, boost, and other components should be in working order to start the regeneration process of the John Deere 4066r.

John Deere 4066r Hydraulic Problems

Problem Solution
Dirty Oil. Hydraulic oil change required. 
Air in the hydraulic system. Air bleeding.
Failed relief valve. Relief valve replacement required.

Insufficient Hydraulic Oil Pressure

Hydraulic fluid will also create many hydraulic problems in the John Deere 4066r. It is essential to keep the fluid level proper to prevent any hydraulic issues. If you notice any clogged hydraulic fuel fluid filter element, don’t mind cleaning it.

Leaking hydraulic pipes can also be a culprit for hydraulic problems. Therefore, you should inspect this John Deere 4066r system for any leak and fix it immediately.

If John Deere 4066r hydraulic is not working correctly, don’t mind installing a new hydraulic pump if it is faulty. The same goes for a faulty hydraulic cylinder. Any deteriorated or worn-out component of your John Deere 4066r should be replaced with the new one.

3-point Hitch Won’t Lift Or Lifts Slowly

Problem Solution
Faulty hydraulic pump. Repair it.
Relief valve malfunctioning.  If the main relief valve is Malfunctioning a replacement may be required.
Defective hydraulic cylinder.  If the hydraulic cylinder is not working properly replace it with the new one; otherwise it will cause insufficient hydraulic fluid.
Insufficient Hydraulic fluid. Refilling required
Clogged hydraulic fluid filter element.  Replace it, if required. 
Excessive Hitch Load. Reduce Hitch Load.

3-poInt Hitch Won’t Lower

  • If the hydraulic cylinder is broken, the hitch will not lower. Therefore replacing the hydraulic system will solve the issue.
  • If the setting of the hydraulic spool valve is incorrect, correct it using the user manual.
  • If The hitch rock is worn out, replace it immediately. 
  • Sometimes, a misadjusted hitch can be a problem that needs proper adjustment.

Hitch Jerks When Drop Or Lift: 

Problem Solution
Dirty hydraulic oil.  Clean & Replace
Faulty Hydraulic pump. Repair or replace hydraulic fluid pump as required. 
Air in a hydraulic system. Bleed air from the system. 
Defective hydraulic spool valve.  Replacement is suggested. 
Faulty hydraulic cylinder.  Replace or repair it as needed.

John Deere 4066r Hydrostatic Transmission Problems

Excessive Noise 

If your John Deere 4066r makes excessive noise, there can be a worn-out speed control linkage. If the speed control linkage is out of adjustment, adjust it properly. Other than this, if it has any sign of wear and wear, replace it entirely.

Due to the excessive load on the transmission, you may hear excessive noise from the hydrostatic transmission system of your John Deere 4066r.

It is essential to reduce the burden, though. Always keep the level sufficient and prevent any contamination. If the relief valve is defective, replace it. The same goes for any other worn-out transmission part or hydrostatic transmission company with defects.

Transmission Fluid Overheated

The transmission fluid will overheat if the excessive load is on the transmission system. Overheated transmission fluid systems could also be related to a clogged or damaged cooling component.

Therefore, check all the congested parts to repair or replace them if needed. If you notice insufficient transmission oil, this can also be the culprit. Never mind changing any dirty transmission fluid fuel filter element.

Low Power

Problem Solution
Faulty hydraulic pump. Repair it.
Low Transmission fluid level is low.  Add if necessary.
Relief valve malfunction.  Replace the valve. 
Faulty Speed control linkage.  If the speed control linkage shows wear and tear, replace it entirely. Other than this, if the speed control linkage is out of adjustment, adjust it according to the user manual.

External Fluid Leaks

Problem Solution
Clogged Oil return tube.  Replace the tube if cleaning is not possible. it.
Worn seals.  Replacement required
Faulty Gaskets. Replacement required. 
High Transmission case internal pressure.  Internal pressure can be extremely high in transmission due to a defective part. Therefore change any wrong details or call The mechanic.

John Deere 4066r fuel consumtion Problems

Adjust The Tyre Pressure 

Depending upon the type of ground, you should maintain your John Deere 4066r type pressure as it can impact your mower fuel consumption.

If your John Deere 4066r mows a field with an over-inflated tire, it will consume more fuel due to excessive slip. To prevent extreme decline, your John Deere 4066r tire needs to draw more power from its engine and compensate for its lost grip.

Use Eco Power Take-off

With most mowers, the tire coming with the machine is only sometimes suitable. Sometimes manufacturing goes with the cheapest one.

Therefore if your John Deere 4066r tire is not friendly for eco-power take-off, please replace it with the better-suited one. If you reduce the engine speed, the eco take-off will give you the same power while using 15-20% less fuel.

Get Vf Tyre

Modifying your mowers with a low-pressure tire will substantially impact your John Deere 4066r fuel consumption.

Within a few months of usage, you will soon recover the additional cost of these tires from all the fuel savings. When installing a VF tire, you are always on top in the long run. This feature was only available with tractors but is now recently available for mowers.

Focus on shallower depths

If you do heavier jobs with a John Deere 4066r, you must take extra care of your mowers. If your John Deere 4066r has a low-pressure VF tire, you can reduce your working depth by several centimeters without harming your crop yields. According to research, reducing the depth by 8 cm can save you 26.39% more fuel.

Reducing Road Speeds

When you constantly check the clock, you try to increase the road speed of your John Deere 4066r as much as possible. However, if you reduce your John Deere 4066r speed by only a few miles, you can save a lot of fuel over the year.

You should drive slowly significantly if the distance is manageable. Even though you will lose a few extra minutes, your John Deere 4066r will consume less fuel making a considerable difference to the end of your financial closing balance sheet.

Correct Weight Distribution

The traction power a John Deere 4066r needs for the work will directly impact fuel consumption. Therefore, if you miscalculate the load transfer, you will never get the full benefit of a John Deere 4066r power because the John Deere 4066r is out of balance.

Considering the tool used, consider increasing the axle load to improve tractor grip and maximum tractive force and prevent slip with zero loss.


Even though John Deere is known for making some of the best tractors and mowers available, every brand has its drawbacks, also. It is essential to keep your John Deere 4066r on routine maintenance to prevent some of the common problems that can arise over time.

Besides, there can be expensive repairs if you don’t pay close attention to minor issues and fixes. If you need more experience repairing vehicles, it is better to take your unit to a professional who can help you.

You need to have excellent knowledge in fixing mowers and tractors to avoid doing more harm than good to your John Deere 4066r.

By far now, you know the most common John Deere 4066r problems that can be fixed if paid attention. Do check our other resourceful guide on tractors. See you in the next post. Till then, take care and goodbye.5 John Deere 4066r Problems

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