John Deere 4620 Problems (The 360-Guidelines)

John Deere 4620 comes with the best specs to make work in the field easier for you. But what if the engine breaks down or the hydraulics start leaking? You better be prepared for that.

John Deere 4620 often faces issues with the engine – not starting, overheating, or shutting down suddenly. Other issues include transmission, hydraulic, and electrical-based problems. Shifting issues, noise problems, leaking issues, hydraulic oil pressure issues, etc. are among them. 

With that being said, how do you solve them? Let’s go through each section to find that out.

John Deere 4620 Engine Problems

Problems Reasons Solutions
Engine Does Not Start Low battery charge, Corroded starter motor, 

Clogged fuel line, Dirty fuel filter, Clogged or damaged injector, Keeping the tractor idle for a long time, Fuel too heavy at low temperature, Faulty piston rings

Charge the battery, clean the starter motor, Clean the fuel line, Change the fuel filter, Repair and clean the injector.
Engine Shuts Off Suddenly Incorrect Fuel Injection Pump Timing setting, clogged fuel filter, and a cold engine Fix the Injection Pump timing, and replace the fuel filter.
Engine Overheats Low coolant level, Clogged radiator, Excess diesel, and Broken fan belt Replace the radiator cap and broken belt, clean radiator, refill the coolant, avoid excess fuel.
Engine Power Loss Faulty fuel injection nozzle, clogged fuel hoses, damaged cylinder head gasket Clean Fuel Injection nozzles, replace fuel hoses.

As observed, a defective fuel system can lead to problems in the engine.

Problem 1: Engine Does Not Start or Hard Start

Typically John Deere 4620 does not start because of a clogged fuel filter. An engine needs the air-fuel mixture to become compressed and ignite to get started.

But a clogged fuel system either because of air or any dirt stops fuel from passing properly. 

The engine can hardly start due to water in the fuel or fuel being too heavy at low temperatures. There can also be issues with the fuel injector or fuel line. 


  • Check engine light coming on
  • Engine Misfire
  • Engine Cranking


  • First, check and charge your battery if it is not properly charged. If your tractor battery cannot hold a charge, your battery is worn out or damaged. Replace the battery if it is old. 
  • If the battery is not the issue, check the connection of the starter motor if it’s corroded. Clean it properly with a corrosion cleaner and see if your tractor works. 
  • Check the fuel line and fuel filter if it is dirty or clogged. Replace the fuel filter and clean the fuel line with a fuel system cleaner. 
  • If the fuel line and filter are working, check for a broken piston or damaged fuel injector. If broken, remove them and replace them with a new one. 

You can follow this video guideline to replace the fuel injector:

  • If all the components are fine, the issue may be the fuel. Change the fuel and your tractor should start properly.   
Replacing the Fuel Filter

Step 1: First, find the fuel filter. But make sure to grab a drain pan and put it beneath to catch all the residual fuel.

Step 2: The fuel filter is in a tab. Push it.

Step 3: Take off the fuel filter. 

Step 4: Now, put the new fuel filter in its place and connect the tab properly.

Step 5: Look for the fuel pump. There is a lever with it. Actuate it.

Step 6: You will see the filter keeps filling with oil. Let it happen until the fuel starts coming out.

Step 7: Finally, wipe the excess fuel and start the engine.

Problem 2: Engine Shuts Off Suddenly

A clogged fuel system can lead to the John Deere 4620 shutting off all of a sudden.

It happens due to clogged fuel filters or unsynchronised injection pump timing. If the engine is not warm, it can also shut off suddenly. 


  • Check Engine Light coming on
  • Rough Idling
  • Declining Fuel Economy


  • To solve the issue, first, check for a clogged or dirty fuel filter. Replace the fuel filter
  • If the fuel filter is working fine, you need to adjust the fuel injection pump timing. Follow this guideline to repair the injection pump timing. 
  • If the issue is a cold engine, simply warm up the engine and normalize its temperature. 

The engine shut-off problem with your John Deere 4620 should be solved now. 

Problem 3: Engine Overheats

Engine gets overheated when it can’t emit the excess heat from the system. It happens whenever the radiator or the cooling fan system is damaged, the coolant level is low or there is excess oil in the diesel tank. 

A broken belt can also overheat the engine of your John Deere 4620.


  • Radiator fluid is rusty colored
  • Unusual smell from the engine


  • First, check the coolant level by detaching the radiator cap. If the coolant level is low, refill it. You can replace the radiator cap when refilling the coolant. 
  • Refill the tank with a 50-50 ratio of coolant and water and fill it up to the mark. Replace the radiator cap with a new one.
  • If the coolant level is full, then check the radiator for dirt or clogs. Clean the radiator’s fins and screen with water. 
  • If the radiator is working fine, a damaged fan belt can be the issue. Replace the fan belt with a new one. 

Problem 4: Engine Power Loss

Any blockage in the fuel system of the John Deere 4620 leads to engine power loss. The main reason for this is defective fuel injector nozzles, clogged fuel hoses, and damaged cylinder head gaskets.

A damaged gasket means that the engine needs more energy to run. More energy means more probability of getting overheated. 


  • Excess smoke
  • Overconsumption of fuel
  • Problem in starting


  • First, clean the fuel injection nozzles by using additives to pass through the nozzles. Or, install new correctly balanced nozzles.
  • If there is dirt or clogs in the fuel hoses, or fuel lines, clean them using fuel system cleaners.  
  •  Replace the air filter and gasket if they are damaged.

Follow this guideline for the replacement process:

John Deere 4620 Transmission Problems

Problems Reasons Solutions
Difficulty in Shifting Worn-out gear shift linkage, malfunctioning shift forks Install shift linkage, and replace shift forks.
Transmission Oil Leakage Damaged gaskets and seals, Excess level of transmission oil Replace seals and gaskets, and maintain transmission oil capacity.
Noisy Transmission Damaged gear, worn-out shift forks, low transmission oil level Replace gear, replace shift forks, and maintain transmission oil capacity.
Low Transmission Oil Pressure Low transmission fluid level, dirty transmission oil filter. Add more transmission fluid, and clean the filter element.

Fixing the gear-based problems can solve most of the transmission issues in John Deere 4620.

Problem 1: Difficulty in Shifting

Difficulty in shifting means rough gear shifting. You may feel a thud when shifting the transmission or it happens due to problems in the shift fork and linkage in your John Deere 4620. 

However, a defect in the gear shift mechanism itself or a worn-out clutch can cause this problem. 


  • Clunking sounds
  • Transmission Oil Leaking


To solve this problem install shift linkage and replace shift forks. It may cost you around $150-$200 to get aftermarket shift linkage and shift forks. 

Problem 2: Transmission Oil Leakage

Any type of leaking is a serious problem. But transmission oil leakage can damage the engine. Some symptoms are a burning-type smell and difficulty in shifting gears. 


  • Low transmission fluid level
  • Maneuverability issues


This problem can be solved by replacing the seal and gasket. However, maintaining the transmission oil capacity can also be a good solution.

Problem 3: Noisy Transmission

One of the key giveaways for a noisy transmission is increased vibration. The main reason for this problem is defective gears and shift forks.

But that’s not it. Worn-out bearings, contaminated transmission oil, and insufficient oil capacity are some key reasons for this problem. 


A noisy transmission is sort of a result of other transmission issues. It in itself is a symptom of other problems. However, some key symptoms are-

  • Low transmission fluid level
  • Gear slipping


Before diving into the solution phase, check the transmission oil. Look for any impurity or if the level is too low or not. If either of those is the reason, either replace or add more transmission oil.

For anything else, the key solution here is to replace the gear and the shift fork. We recommend consulting a professional for this task. 

Problem 4: Low Transmission Oil Pressure

This issue in John Deere 4620 can occur if the transmission fluid level is low, or the transmission oil filter element is dirty. 


  • The Check Engine Light or the Transmission Warning Light will be on
  • There may be some noises or burning smell
  • Poor acceleration 
  • Slow or slipping gear engagement 


  • First, get an accurate reading of your transmission fluid level. Make sure the tractor is cold and on level ground. 
  • Now, the reservoir is located near the driver’s seat. Open the reservoir cap, pull the dipstick out and check the level. If the transmission fluid level is low, you need to add more transmission oil. 
  • To add transmission fluid, take a funnel and slowly pour the fluid into the reservoir. John Deere uses Hy-Gard and low-viscosity Hy-Gard transmission oil. 
  • Pour the transmission oil in the oil filter reservoirs up to the full line to avoid overfilling. The line is marked on the reservoir tank sidewall. 
  • Put the dipstick back in and close the cap. 

If your John Deere 4620 tractor has enough transmission oil, the problem may be the transmission oil filter element. 

John Deere 4620 Hydraulics Problems

Problems Reasons Solutions
Insufficient Hydraulic Oil Pressure   Not enough hydraulic oil, blocked hydraulic oil filter, leaking hydraulic pipe, faulty hydraulic pump and cylinder Maintain sufficient hydraulic oil, Repair leaking pipe, Replace hydraulic filter, pump or cylinder. 
Hydraulic System Overheats Air stuck in the hydraulic line, using incorrect hydraulic fuel Bleed air, Use the correct type of hydraulic fuel.
Hitch Not Raising Malfunctioning hydraulic pump and valve Replace hydraulic pump, replace hydraulic valve.
Hitch Not Lowering Dirty hydraulic oil, faulty hydraulic cylinder, damaged shaft, 3-point hitch not adjusted Replace hydraulic cylinder, Replace shaft, Adjust 3 point hitch.

Working with the pump and cylinder can solve the problem related to Hydraulics. 

Problem 1: Insufficient Hydraulic Oil Pressure

Neglecting this problem can lead to increased wear and tear in your John Deere 4620 engine.

If there is not enough hydraulic oil, leaking hydraulic pipes, or the hydraulic pump and cylinder are faulty, the system may have insufficient oil pressure. A clogged hydraulic filter can also cause this issue. 


  • Leaking hydraulic oil
  • Increased engine noise


  • First, check the hydraulic oil level. If it is low, add more oil. 
  • Clean the hydraulic oil filter if it is clogged. 
  • Locate the pipes connected to the hydraulic system. Check for sources of leakages. If there is any, replace it. 
  • If the spool valve is loose, adjust the valve. 
  • Check for defective hydraulic pumps and cylinders. Install a new one if they are damaged. 

Problem 2: Hydraulic System Overheats

One of the major consequences of hydraulic system overheating is the hydraulic pump failing. This in turn can lead to other problems related to the hitch.

The wrong hydraulic fluid type or contaminated hydraulic oil can also result in system overheating. 

Air in hydraulic lines or a damaged main relief valve can also cause this issue. 


  • Leaking hydraulic oil
  • Burning of seals


  • First, bleed air from the hydraulic line. The process is discussed below. 
  • If the problem isn’t solved, check if the hydraulic fluid is contaminated or if the wrong grade of hydraulic oil is used. 

Usually, John Deere recommends you to use Hy-Gard Hydraulic oil. But using any hydraulic oil with ISO grade 46 or above will work fine for the John Deere 4620 tractor.

  • Replace the main relief valve if the problem isn’t still solved.  
Bleeding the Air from Hydraulic Line

Following are the steps for bleeding air from the hydraulic line. 

Step 1: Locate the fuel transfer pump

Step 2: Find the bleed valve on the side of the pump

Step 3: Pump the primer until there is only fuel coming out of the injection pump

Step 4: Close the bleed valve

Step 5: Find the high-pressure lines at the fuel injector nozzles

Step 6: Loosen the high-pressure lines

Step 7: Crank the engine until fuel leaks out of the loose lines

Step 8: Tighten the lines and start the tractor

Problem 3: Hitch Not Raising

Hitch not raising makes the purpose of the John Deere 4620 tractor quite obsolete. If the hydraulic pump or main relief valve malfunctions, the hitch may not raise.

A faulty hydraulic control valve, damaged cylinder, or clogged hydraulic oil filter can also cause this issue. 


  • Low hydraulic fluid
  • Clogged filter
  • Decreased pressure


First, check for low hydraulic oil levels and refill it if it is insufficient. If the problem persists, change the relief valve and hydraulic valve and see if it’s solved. If the hitch is still not raising, replace the oil filter.

This problem can be solved by replacing the hydraulic steering pump if none of the above are at fault. The process has been discussed here.

Step 1: Take off the cover.

Step 2: Locate the steering pump along with the steering column.

Step 3: Loosen the bolt connected to the steering pump.

Step 4: Take out the pump with the column.

Step 5: Unbolt the pump from the column.

Step 6: Pull out the shaft from the pump.

Step 7: Take the new pump and connect the shaft with it.

Step 8: Connect the bolts and put it back inside the tractor.

Step 9: Connect back all the bolts.

Step 10: Close the cover.

Problem 4: Hitch Not Lowering

The hitch can also cause problems related to lowering. A faulty hydraulic cylinder, loose hydraulic control valve, and damaged lift arm shaft are the reasons. If the hitch is not properly adjusted, it can also fail to respond. 


  • Decreased pressure
  • Damaged seal


First, adjust the hydraulic control valve, and 3-point hitch, or replace the lift arm shaft. If it does not work, this problem is solved by repairing the hydraulic cylinder.

John Deere 4620 Steering Problems

Problems Reasons Solutions
Steering Wheel Excessive Free Play Worn-out steering column coupling, damaged steering control valve, defective hydraulic steering pump Replace steering pump, change steering control valve, change hydraulic steering pump.
Steering Wheel Too Difficult to Move Air stuck in the steering system, insufficient steering oil, front tires not worn evenly Bleed the steering system, Maintain sufficient steering oil, replace tires.

John Deere 4620 troubleshooting for steering system includes solving problems in the steering pump and control valve. 

Problem 1: Steering Wheel Excessive Free Play

Excessive steering wheel free play makes controlling the wheel difficult. The reasons are faulty steering column coupling, steering control valve, or hydraulic steering pump. 


  • The tractor overturns when taking a turn.
  • The steering wheel will shake at high-speed.
  • There may be a knocking sound during bumps.


First, replace the steering pump if it is defective. The process of replacing the hydraulic steering has been discussed above.

If the problem is with the damaged steering Control Valve, you need to change it. Due to the relatively complicated nature of the process, we recommend consulting a professional for this process. 

Problem 2: Steering Wheel Too Difficult to Move

On the other hand, the steering wheel being too difficult to move can also be irritating. The steering wheel can be hard to move due to air stuck in the steering system or low steering oil. 


  • Increased tire pressure
  • Leaking fluid
  • Damaged serpentine belt


  • To let out the trapped air, you need to bleed the steering system. 
  • If the problem isn’t with the steering system, replace the tires if they are not evenly worn.

Step 1: Turn off the engine.

Step 2: Elevate the tractor using the jack stand.

Step 3: Loosen the bolts connected to the front wheels.

Step 4: Rotate slowly and remove the front wheels.

Step 5: Pull the tire off the wheel rim using a crowbar.

Step 6: Stand the tire up and pull out the rim.

Step 7: Put the rim in the new tire.

Step 8: Connect the wheel to the tractor. 

Now, your John Deere 4620 tractor steering wheel should operate properly. 

John Deere 4620 Electrical Problems

Problems Reasons Solutions
Battery Does Not Charge Improper or loose wiring, corroded or damaged battery Tighten wire connection, Replace battery.
Starter Does Not Work Battery not charged, damaged battery, damaged starter Charge battery, replace the battery, replace starter.

Most of the problems can be solved through battery servicing

Problem 1: Battery Does Not Charge

John Deere 4620 can face the battery not charging properly as a common electrical problem. Corroded wires, loose connections, faulty battery terminals or battery cells, and a faulty belt can cause the issue.  


  • Damaged alternator
  • Malfunctioning electrical system


  • First, check for loose or corroded wires. Clean the corrosion with a corrosion cleaner and tighten the wire connection. 
  • Check for loose battery terminal connectors. If they are loose, tighten the connection. 
  • If the belt is loose or damaged, replace the belt and make sure the belt tension is properly adjusted. 

If none of the solutions work, replace the battery. 

Replacing the Battery

Following are the steps for replacing the battery for the John Deere 4620.

Step 1: Turn off the engine. 

Step 2: Pop the hood and locate the battery.

Step 3: The battery has both left and right-hand sides as shown in the operator’s manual.  

Step 4: Remove the negative ground cable from the left-hand battery first.

Step 5: Remove the connector cable from the right-hand battery.

Step 6: Remove the positive ground cable from the right-hand battery.

Step 7: Remove the battery hold-down clamp.

Step 8: Lift up the battery from the tray.

Step 9: Clean the tray.

Step 10: Put the new battery in.

Step 11: Connect the positive ground cable first.

Step 12: Connect the connector cable at the right-hand.  

Step 13: Connect the negative ground cable.

Step 14: Tighten the battery and hold down clamp.

Step 15: Close the hood and turn on the engine. 

However, it is recommended that you clean the battery with a damp cloth after every 200 hours of operation. 

Problem 2: Starter Does Not Work

Starter not working properly is also related to the battery and the starter itself.

If the battery is defective or needs charging, low battery capacity, improper wiring harness connection, and faulty starter motor are the reason for the starter not working. 


  • Clicking sound when turning the ignition on
  • Loss of power
  • Smoke from the engine


Identify if the battery is drained or damaged. If it needs charging, you can follow this process. 

Step 1: Turn off the engine.

Step 2: Pop the hood and locate the battery.

Step 3: Connect the positive cable of the charger to the positive terminal of the battery.

Step 4: Connect the negative cable to the negative terminal of the battery.

Step 5: Turn on the charger.

Step 6: Keep it charging for around 10 hours and then remove it.

Step 7: Close the hood and turn on the engine.

Check the battery wiring harness if it is loose or incorrectly connected. If the battery is nearing its life, or the battery capacity is low, it’s better to replace the battery. The steps for replacing the battery have already been discussed above.

If the battery is not faulty, check the starter motor and if necessary, replace it. The process is as below. 

Step 1: Remove the cover and locate the starter.

Step 2: Remove the negative cable first.

Step 3: Remove all the nuts connected to the starter.

Step 4: Remove the switch wire connected to the starter.

Step 5: Take off the starter.

Step 6: Put the new starter.

Step 7: Connect all the nut to the starter.

Step 8: Connect the switch wire to the starter.

Step 9: Connect the negative cable back.

Step 10: Close the cover and turn on the engine.

Therefore, this is how you detect and solve the common problems related to John Deere 4620. 


So that covers the common John Deere 4620 problems. It should answer all your questions on different types of problems. Hopefully, you can solve them as well. 

Most of them can be easily solved. For more content like this, comment below on what we should write next.

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