The John Deere 4320 is a fantastic machine and one of the most popular tractors for sale. It was made because there was a huge gap in John Deere’s offerings, and there was nothing that could fulfill the needs of people who needed something bigger than the 4020 but smaller than the 4520. We love the 4320 tractors and believe that these are a classic in the world of tractors. The transmission of the 4320 is extremely reliable, easily one of the most reliable transmissions we have seen.

This doesn’t mean that it is impossible to break though. One way we have seen them break is when some inexperienced drivers use the downshift as if they were a brake; this is the easiest way to ruin your transmission. It can also be affected by some other conditions, bad drivers are not the only way to break the transmission, and bad driving conditions may be the culprit. If your John Deere 4320 transmission is not working as it should then you need to learn how to repair it. We will be assuming you know a bit about tractor repair already, if you don’t then we would recommend doing this with someone who does.

The most intimidating part of the whole process is getting to the engine. When you work with cars it is easy and it looks safe. You press one button and the whole engine is exposed. Even people who know how to work on cars have trouble getting started with tractor repairs. They simply cannot understand where to start because there is no hood that can get you access to the transmission. Car mechanics don’t know that tractors split apart. Most of the other items in the tractor work in a similar fashion to cars.


Once you have the tractor opened up you will be able to fix your transmission easily. This guide will let you know what you need to remove and in what order to get to the transmission. We had to open one of these up when one of our syncro-drums broke and fell down the transmission. The sound of something dropping inside the engine is one of the most worrying sounds a driver can hear, because often it means that whatever broke damaged something else as well.


Splitting up the Tractor

This might seem weird if you haven’t worked on tractors before, but the first thing you need to do in order to repair the transmission of the 4320 is split it. You cannot get in to the transmission the way one does with cars by popping the hood, you have to split the machine into two parts. The split actually happens right where the transmission is. Look at the bottom shaft, where the PTO and the gear parts are visible. You will be able to see a snap ring here which will be holding the gear on. You need to remove this snap ring in order to be able to repair the transmission.

Once you have removed the snap ring that holds the gear together, take out the gear. Behind the area where the gear was you will find another snap ring. You have to compress this snap ring and then you can remove the PTO shaft from behind. Do note that it is possible that you have the power shift instead of the syncro-range like we do. If you have a power shift then the process is almost identical but the PTO is a bit different.


We often hear that people have problems removing the nuts in order to split the tractor; if you haven’t opened them up for a long time then you may have problems too. Usually if you just apply a bit more pressure they might come off, but sometimes they do not. If you have any nuts stuck then we recommend putting some heat on them. Only do this if you have a safe environment to do it like we do, otherwise this could end up damaging the tractor somehow.


If you cannot apply heat as required, you can try putting on force on the nuts. Try applying pressure with a wrench then having someone else hit it with a hammer as well. Once again, this requires a lot of safety otherwise you will end up with an injury. Only do this if you can guarantee the safety of you and the people around you. Start with light hits, they should be enough to dislodge the nuts and free them again. Don’t worry, this ends up happening when you open up old machinery. Head to for a precise outline regarding torque wrench efficacies


Remove the Rockshaft Housing

In order to get to the shafts of the 4320 you will have to remove the rockshaft housing. Removing the rockshaft housing can be a hard thing to do. The biggest problem is that the rockshaft is a bit heavy and has to be removed in a technical manner. You will definitely need another person to hold the rockshaft housing as you take it off. This is not too dangerous, just be sure it doesn’t get dropped while you are working on it.

Below the drums you will find the transmission. From now on what you have to do is find out what is wrong with the transmission and fixing it. If you have a parts issue, simply replace the parts. Proper maintenance from the inside can also help get things going again, if you think the transmission has started to get stuck a little. Once you are inside the tractor after having opened it up, the job is simple.

Keep it maintained

Once you have opened up a tractor successfully it will not feel hard anymore. We recommend taking these apart every few months and doing proper maintenance. Getting a good look inside also alerts you about small problems and lets you fix them before they turn into bigger problems. Opening up the tractor also increases your technical knowledge; you will be surprised at how well you know repair and maintenance work in a short time.

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