John Deere 790 Specs and Review

The John Deere 790 is undeniably one of the best multi-use tractors anyone can buy. But the question is, is it also suitable for you? What are the specs of the John Deere 790? What things do you need to know about it to make your decision easier? Find the answers through this John Deere 790 specs and review article.

The John Deere 790 is a utility tractor developed by Yanmar of Japan for John Deere. This tractor came with a 30-horsepower (20kW) Yanmar engine. The Yanmar 3TNE84 is a diesel-powered, 3-cylinder, liquid-cooled, 1.5L displacement engine. What’s good about this engine is it can produce more than enough power for most farm and ranch tasks.

Continue reading this John Deere 790 specs and review to make an informed decision.

John Deere 790 Review

John Deere 790

Most of the jobs and tasks involved in farms and ranches require using a powerful utility tractor. However, even the cheapest tractors on the market can still cost much money. This is the reason why farmers and ranchers are quite peculiar when making their purchasing decisions.

If you think that way, the John Deere 790 tractor might be the thing you are looking for. It is an excellent choice to get the most bang for your buck.

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Why Is the John Deere 790 Famous Among Farmers

Why is the John Deere 790 famous among farmers, ranchers, and anyone who owns a rather large property? Here are some of the reasons:

1. Engine

A large displacement Yanmar diesel engine powers up the JD790. The liquid-cooled engine from the TNV Series of Yanmar can produce 27 horsepower. It also has a large power reserve when you need the extra boost for more challenging and power-intensive tasks.

Additional features of the Yanmar engine include:

  • Fuel injection
  • Cylindrical solid cast-in block
  • Cast-aluminum material for pistons
  • A high-efficiency lube system

2. Transmission

Farmers buy tractors because they have multiple purposes. It is compatible with a variety of attachments, like backhoes and loaders.

The John Deere 790 comes explicitly with an 8×2 sliding gear transmission. You can see it is partnered with a transmission case made of cast-iron material.

The transmission is not only solid and durable enough that it can hold heavy attachments. It also uses a single reservoir for transmission, a hydraulic system, and differential fluids. This makes it easier and quicker to maintain since you only need to monitor the fluid level of one reservoir.

3. User-Friendly Cockpit

You can quickly and conveniently get on or off the John Deere 790. This is all thanks to the handrails and side-step positioned on the fenders.

It has a rubber-mounted foothold and comes with a non-skid and self-cleaning surface. This means you can quickly get on and off the tractor, even during inclement weather.

In addition, the John Deere 790 features a high-backed driver’s seat, providing maximum support and comfort.

The seat also folds down, offering protection from the harsh elements. The 790 also came standard with a 2-post roll cage. This can protect the driver if the tractor tips over accidentally.

Brief History of John Deere Tractors

John Deere, the company’s namesake, was a blacksmith who invented the first commercially successfully self-scouring steel plow. This is the product that put the John Deere company on the map.

Born in 1804 in Vermont, Deere lost his father when he was four. He was then raised by her mother alone. When he was still young, John Deere received lots of acclaim for his skills and workmanship as a professional blacksmith.

Following the New England economic collapse in 1836, Deere migrated to Illinois, where he started a blacksmith shop.

After setting up his blacksmith shop, Deere learned that his customers, primarily farmers, typically used cast-iron plows.

The sticky soil of the Midwest farmlands would usually cling to the plow. This meant that the farmers would need to stop and scrape off the mud every couple of feet or so.

Deere believed that using a plow with a highly polished plow surface would remove the sticky soil itself. He created his first plow using a broken sawblade and gave it a polished surface, calling it the self-scouring plow.

Hundreds of farmers gathered for the first time. Deere tested his self-scouring plow. It did not take long before he became known for his plows, and it became his business’ identity.

In 1918, John Deere dove into the industry for which the company will be most well-known, farm tractors. It manufactured its first two tractor models to bear the John Deere logo – the John Deere Tractor and Waterloo Boy.

John Deere 790 Specs

The John Deere 790 is one of the most popular tractors made by the company. If you are interested in getting one, here are some specs that you need to take into consideration:

1. HP/Engine

The John Deere 790 was first introduced with the Yanmar 3TNE84, 3-cylinder, diesel-powered, liquid-cooled 1.5L engine. This engine has a dry air cleaner. It also can produce up to 30 horsepower (22.4 kW).

The Yanmar diesel engine has a bore/stroke of 3.3″ x 3.5″. It also possesses a compression ratio of 18:1 and a motor rated for 2600 rpm.

2. Battery

As for the battery, it comes in the form of a 12-volt battery with 500 cold-cranking amps.

3. Transmission

The John Deere 790 comes standard with an unsynchronized transmission. It has eight forward and two reverse gears, with a transmission oil capacity of 15.1L. It also uses low-viscosity HY-Gard oil.

4. Weight and Dimensions

The John Deere 790 is quite a compact tractor. It has a 60.4-inch wheelbase and weighs around 1,930 pounds. This tractor has a height of 51.2 inches at the hood, and 82 inches total, including the roll bar.

5. Price

You can get a secondhand John Deere 790 unit for around $11,950. Depending on what attachments come with the tractor, the price can still go up or down.

If you want, you can also get a cheap project tractor. You can usually find a non-running but still repairable John Deere 790 tractor for a couple of thousands of dollars. You will then need to sink another thousand dollars to fix and restore it.

John Deere 790 Pros and Cons

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The John Deere 790 is an excellent piece of machinery. It may not have the same bells and whistles as the other more modern tractors. Despite that, it still has its share of benefits:

1. Easy to Access Engine

Other modern tractors come locked behind a DRM, so you cannot even do your maintenance. This is not the case with the John Deere 790 engine, as it is open for anyone to access.

Aside from changing the engine oil and other fluids, you can also change the engine belts. You can completely rebuild the engine if you want or are capable of it.

2. Incredible Safety Features

This John Deere tractor has all the safety features you expect from larger models. For instance, the 790 has a PTO and transmission operator presence system.

This prevents the tractor from operating when no one is sitting in the driver’s seat. The tractor also comes with a sturdy roll cage that will protect you in case of accidental rollovers.

3. Comfortable Operator’s Seat

Speaking of the seat, the operator’s seat of this tractor is one of the most comfortable. It is comfortable if you have a large yard and need to work on land for a few hours daily.

4. Reliable Engine

Even the older models of the John Deere 790 tractors are still quite reliable. The engine would start immediately, thanks to the direct fuel injection system. Even on cold days, starting the diesel engine is relatively easy.

Again, what year did they make the 790 John Deere tractor? The John Deere 790 tractor was introduced in 2000, then discontinued in 2002. This utility tractor has a diesel-powered, 3-cylinder, liquid-cooled, 1.5L displacement Yanmar engine that is enough power for farm and ranch tasks.


Although the 790 has many benefits, it is not the perfect tractor, far from it. It also has a couple of downsides, including the following:

1. Weak Lift Capacity

The John Deere 790 has a weaker lift capacity than other similar-sized tractors. It is still acceptable, but you might be left wanting more power, especially if you are in a hurry.

The tractor can still plow through relatively hard soil. However, if you are going to pull out tree stumps, it might not be powerful enough.

2. Weak Battery Terminals

The battery terminals of specific models are pretty weak. You will find that you will be tightening the nuts every month or so. You may think that the battery died, but the terminals are just loose.

John Deere 790 Attachments

You can make more use of your John Deere 790 by using attachments. In that case, here are some commonly used attachments with the 790 tractors:

1. 60″ Mower Deck

You’d love to use this large mower deck attachment if you have a large lawn. This mowing deck is 60 inches wide. It has three blades and a hydraulic lift to adjust the cutting height.

Speaking of the cutting height, you can adjust it from between 1-inch to 8.75-inches. The mowing deck is quite heavy at 325 pounds. However, when hitched to the tractor, it will not be that much of a problem.

2. 70 Loader Attachment

The John Deere 70-loader attachment is one of the most famous attachments. This means it is not just for the 790.

This loader has a bucket capacity of 0.1 cubic meters and a total height of 77 inches. The dumper can reach 31 inches vertically and 46 inches into the ground.

3. 7 Backhoe

You can also attach a backhoe to your John Deere 790, turning the tractor into your construction machinery. However, like the loader attachment, the backhoe attachment is not quite as big as a regular backhoe bucket.

The digging depth of the backhoe is around 90 inches, which is quite respectable for something so small. The bucket can also load to a height of 70 inches. It can also apply a force of up to 882 kilograms (1945 pounds). The bucket attachment also weighs around 787 pounds.

John Deere 790 Problems

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When shopping for a John Deere 790 tractor, you need to know its common problems. Here are some common issues that John Deere 790 owners usually experience. You will also get an idea of how you can fix them yourself:

1. Starting Issues

A well-maintained John Deere 790’s engine should start after just one ignition click. However, there are some times when the engine won’t even turn over due to the following issues:

Gearshift in Drive

Usually, this happens when the gearshift lever is still in gear. Make sure to put the gearshift in neutral before cranking the ignition again. Also, the engine throttle lever might not be pushed forward enough. Move the throttle lever to half throttle position and then try again.

Loose Battery Connection

This is another reason you might have trouble starting your tractor engine. The battery connection may be loose or corroded.

If corroded, follow the steps below:

  • Remove the terminals from the battery.
  • Use a wire brush to clean the terminals and connections.
  • Reconnect the battery to the car and ensure the connections are tight. If the engine doesn’t turn over, the battery might die already.

Fuel Shutoff Valve Close

The fuel shutoff valve should be open. The fuel shutoff valve ensures that the ignition chamber is not flooded by fuel. However, if closed, there won’t be enough fuel to start the engine. Ensure that your fuel shutoff opens halfway, so there will be fuel reaching the engine.

Stale Fuel

If you are buying a secondhand tractor, ensure the fuel still in the tank is not stale. Stale diesel fuel is not as easy to ignite as the new fuel.

Remove the gas cap and take a whiff to check if the fuel is stale. Stale fuel smells very different than good fuel. If the fuel in the tank is stale, drain it entirely and put new fuel in the tank.

2. Fuel Issues

There are also times when the engine does not get enough oil. Usually, the filter gets plugged up with debris, preventing oil from circulating throughout the engine. This will also prevent fuel from getting into the ignition chamber.

There might also be a problem with the fuel line. For instance, there might be a tiny pinhole in it. This may cause air to get into the fuel line. If this is the case, you need to check the injector pump.

Also, you should empty the fuel pump and clean it thoroughly. Make sure that the tank is entirely debris-free. After that, clean the filter.

Disconnect the fuel lines to the filter and blow compressed air through them. Plug the line and check if they can maintain the vacuum. If the line cannot hold a vacuum, it might mean a pinhole in the line.

3. Drive Belt Issue

There could be an issue with the drive belt when the tractor has trouble moving forward or back. Another sign is if it smells like there is burning rubber when you are driving the tractor.

To fix this issue, you will need to replace the belt. Here’s how you can do it:

  • Disconnect the spark plug and detach the battery – Open the hood and remove the spark plug wire. Take a wrench and remove the terminals from the battery. It might be a good idea to clean the terminals right now.
  • Disconnect the ground drive belt – Take off the engine pulley bolt. After that, remove the engine pulley from the crankshaft. This will allow you to release the drive belt from the guide.
  • Install the new drive belt – Grab it and loop it over the transaxle pulley. Reposition all the bolts, reconnect the cables, and reinstall the engine pulley. Reconnect the spark plug cable and the battery terminals.

Try running the tractor immediately after replacing the drive belt. The belt might be a bit loose if it makes a lot of noise. Adjust the tension on the pulley until the noise goes away.

In Closing – John Deere 790 Specs and Review

The John Deere 790 is a practical tractor developed by the Japanese company Yanmar for John Deere Tractors. The JD 790 came with a 30-horsepower, diesel-powered, 3-cylinder, 1.5-Liter displacement engine.

The John Deere 790 is more compact compared to its contemporaries. Despite that, it can still produce more than enough power for most required tasks.

Although you cannot find brand new John Deere 790 tractors today, plenty is in the secondhand market. The good news is that you are now aware of the benefits and the problems that the JD790 has. With this knowledge, you can shop for your new tractor with confidence.