The five types are gear, friction disc, automatic, CVT, and hydrostatic. I’ll spend a few minutes going over each type so you have a better idea of the best type for you. I won’t go into the details of how each one works. Just google the type of stream and you can read as much as you want.
Gear
Five years ago, the gear drive was the most popular, but today hydrostatic and automatic transmissions have replaced them in popularity. Often called manual transmissions, this type uses a series of gears to change the forward speed of your tractor. The major disadvantage of this type of transmission is that you must stop the tractor to shift to a different gear (range). This makes them more difficult to use when you have a lot of garden beds and landscape features to go around.
To drive the tractor, you have to depress the clutch, shift the transmission to the gear you want to use, release the clutch, and wait. This is a dependable transmission that will give you years of service.
friction disc
This is actually the transmission of choice for snow blowers, but there are some riding mowers like the Snapper Rear Engine Rider that use this transmission. It’s a good, reliable transmission when used correctly. It uses a friction wheel and a disc to change the forward speed of its rider. Do not use this transmission to pull heavy loads…it will break the friction wheel.
You can shift on the fly with some models, but for the longest life most makes suggest that you depress the clutch/brake pedal and then shift into whatever gear you want.
Automatic
This is essentially a variable belt and pulley system similar to the drive system on a snowmobile. John Deere originally used this in conjunction with a manual transmission on the Model 110. Today MTD uses it on most of their cheaper riding mowers. Like the friction disc, this transmission is designed for the mower application and is not designed to pull heavy loads. Some of the makes have confused the problem by calling their cheap hydrostatic transmission “automatic” so if you’re unsure please ask.
To drive the tractor, you normally have two levers. One for forward or backward and the other for speed. Move the F/R lever to the direction you want to go and then simply move a fender-mounted lever to change speed. This is a dependable transmission that will give you years of service on flat grass and towing very light loads.
CVT/IVT (Continuously/Infinitely Variable Transmission)
The automatic mentioned above and the hydrostatic below are essentially CVTs, but today this means a variable disc or ball/disc system. This is the transmission of the future because it uses fewer moving parts than a gear drive and less oil than a hydrostatic, but right now they are not yet cost effective for riding mower applications. MTD tried using the dual Infinitrak IVT in the Cub Cadet and Craftsman Revolution, but consumers weren’t willing to spend the extra money to purchase this type of transmission. New Holland is using them effectively on its 50hp and larger tractors.
These transmissions are very easy to use. A fender-mounted lever or foot control varies speed and direction.
Hydrostatic
The most common transmission for lawn tractors today is a form of continuously variable transmission called a hydrostatic transmission. These transmissions take various forms, from pumps driving separate motors, which may incorporate a gear reduction, to fully integrated (enclosed) units containing a pump, motor, and gear reduction. Hydrostatic transmissions are more expensive than mechanical transmissions, but they are easier to use and can deliver more torque to the wheels compared to a typical mechanical transmission.
Hydrostatic – Simple closed
These transmissions are very easy to use. A fender-mounted lever or foot control varies speed and direction. The enclosed hydrostatic transmission is a single unit that houses the variable pump, motor, differential, and drive shaft. Most of today’s lawn tractors, garden tractors, garden tractors, and family tractors have an aluminum housing to give off the heat that is generated by moving oil. These transmissions are sized for the mower application. Transmissions on yard tractors and family tractors are designed to handle heavy loads and attachments that stick to the ground.
These transmissions are very easy to use. A fender-mounted lever or foot control varies speed and direction. The pedal on the left side of the tractor is the parking brake. You don’t need to step on that pedal to shift the tractor. Forward and reverse are controlled by a lever on the right fender or two foot pedals on the right side floor. To move forward, push the fender lever forward or press the large pedal on the floor. To stop the tractor, pull the lever back to the middle position or lift your foot off the pedal. To back the tractor, pull back on the fender lever or depress the small foot pedal on the floor.
On the fender-mounted control, you MUST move the lever to the center to stop the tractor. It will not go to neutral by itself like the foot controls.
Hydrostatic – Double closed
Two hydrostatic transmissions are mounted side by side in the residential zero turn. Each trans controls a separate rear wheel. That is the main reason why zero turn mowers cost more than lawn tractors. Again, these trans are designed for the application and most are not designed for pulling loads, just cutting and bagging.
Most of these transmissions are controlled by individual levers that are located in front of you. With a little practice they are very easy to use. A large lever on each side of the seat controls that side drive. To advance, push BOTH levers. To stop, pull them back. (The easiest way to explain how to drive a two-lever zero-turn mower is to use a shopping cart as an example. With the mower turned off, sit on the seat and place your hands on the two large levers in front of you. you. Close you look and pretend you are holding a shopping cart. What do you do to move a shopping cart forward? To the right, you push the handle. To go backward? To the right, you pull the handle. To go to left? To go right? Correct, PUSH the handle in the direction you want to turn the cart. Two zero turns of the lever work the same way. Instead of a bar like a shopping cart, the bar moves splits in two and you move each side to make it move .) This type of drive takes practice to keep the tires from sinking into the grass.
hydrostatic pump and motor
More expensive zero-turn commercial mowers, stand-up mowers, and some golf course mowers use a separate variable pump near the engine connected to the wheel motors with hydraulic hoses or metal lines. They are typically cast iron for long life and durability. Some of the higher end commercial mowers now use cast iron enclosed hydros.