Lawn Tractor Transmission Types Updated: Feb 2011
The fives types are gear, friction disk, automatic, CVT, and hydrostatic. I’ll spend a few minutes going through each type so you have a better idea of the best type for you. I am not going into the details of how each one works. Just Google the transmission type and you can read to your heart’s content.
Gear
Five years ago the gear drive transmission 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 ground speed of your tractor. The biggest downfall of this type of transmission is you have to stop the tractor to shift to a different speed (range). This makes them harder to use when you have a lot of garden beds and landscape features to go around.
To drive the tractor you must push in on the clutch, shift the transmission to the gear you want to use, release the clutch, and hang on. This is a dependable transmission that will give you years of service.
Friction Disk
This is actually the transmission of choice for snow blowers but there are a few mowers like the Snapper Rear Engine Rider that use this trans. It is a good, dependable transmission when used properly. It uses a friction wheel and disk to change the forward speed of your rider. Don’t use this transmission to pull heavy loads…you will tear up the friction wheel.
You can shift-on-the-go with some models but to get the longest life most brands suggest you push down on the clutch/brake pedal and then shift to the speed you want.
Automatic
This is essentially a belt and variable pulley system similar to the drive system in a snowmobile. John Deere originally used this in conjunction with a manual transmission on the Model 110. Now days, MTD is using this on most of it’s cheapest lawn tractors. Like the friction disk this trans is designed to the mower application and they are not designed to pull heavy loads. Some of the Brands have confused the issue by calling their inexpensive hydrostatic trans an “automatic” so if you are unsure ask.
To drive the tractor you typically have two levers. One for forward or reverse and the other for the speed. Move the F/R lever to the direction you want to go and then simply move a fender mounted lever to change the speed. This is a dependable transmission that will give you years of service for flat lawns and pulling very light loads.
CVT/IVT (Continuously/Infinitely Variable Transmission)
The automatic mentioned above and the hydrostatic below are essentially CVT’s but now days this means a variable disk or ball/disk system. This is the transmission of the future because it uses fewer moving parts than a gear trans and less oil than a hydrostatic, but at this point in time they are not yet cost effective for lawn tractor applications. MTD tried using the dual IVT Infinitrak in the Cub Cadet and Craftsman Revolution but consumers were not ready to spend the extra money to own this type of transmission. New Holland is using these effectively in their 50 hp and larger tractors.
These transmissions are very easy to use. Either a fender mounted lever or foot control varies the speed and direction.
Hydrostatic
The most common transmission for lawn tractors today is a form of continuously variable transmission called the hydrostatic transmission. These transmissions take several 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 transmit greater torque to the wheels as compared to a typical mechanical transmission.
Hydrostatic - Enclosed Single
These transmissions are very easy to use. Either a fender mounted lever or foot control varies the speed and direction. The enclosed hydrostatic transmission is a single unit that houses the variable pump, motor, differential and drive axle. Most of lawn tractors, yard tractors, garden tractors and estate tractors today have an aluminum housing to give off the heat the moving oil creates. These transmissions are sized to the mower application. The garden tractor and estate tractor transmissions are built to handle heavy loads and ground engaging attachments.
These transmissions are very easy to use. Either a fender mounted lever or foot control varies the speed and direction. The pedal on the left side of the tractor is the parking brake. You do not need to depress that pedal to shift the tractor. The forward and reverse is controlled by either a lever on the right fender or two pedals on the right side floorboard. To go forward push the fender lever forward or press on the large pedal on the floor board. To stop the tractor pull the lever back to the middle position or lift your foot off the pedal. To back the tractor up pull the fender lever to the rear or press the small pedal on the floorboard.
On the fender mounted control you HAVE to move the lever to the middle to stop your tractor. It will not go to neutral by itself like the foot controls.
Hydrostatic - Enclosed Dual
Two hydrostatic transmissions are mounted side-by-side in the residential zero turns. Each trans controls a separate rear wheel. That is the primary reason why zero-turn mowers cost more than the lawn tractors. Again these trans are designed for the application and most are not designed to pull loads, just mow and bag.
Most of these transmissions are controlled by individual levers that sit in front of you. With a little practice these are very easy to use. A large lever on each side of the seat controls that side transmission. To go forward push on 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 put your hands on the two large levers in front of you. Close you eyes and pretend you are gripping a shopping cart. What do you do to move a shopping cart forward? Right, you push on the handle. To back up? Right, you pull back on the handle. To go left? To go right? Correct, you PUSH the handle in the direction you want to turn the cart. Two lever zero turns work the same way. Instead of one bar like a shopping cart, the bar is split in two and you move each side to make it move.) This type of transmission takes practice to keep the tires from digging into your lawn.
Hydrostatic -Pump & Motor
The more expensive commercial zero-turn mowers, stand-ons, and some golf course mowers use a separate variable pump near the motor connected to the wheel motors with hydraulic hose or metal lines. These are usually cast iron for long life and durability. A few of the high-end commercial mowers are now using enclosed cast iron hydros.
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Hey Paul I have asked questions about my '09 Exccellerator before and from what I understand it has a hydrogear G730 trans. in it however I have not been able to get any specs on it. By specs I mean how musch it can to what the best tire sizes are and any other info I can get on it. I push my tractor to the limit a lot and I question myself sometimes whether or not I should tow 1000 lbs. of logs in my tow behind cart up a hill or pull a 30 foot tree out of the woods or pull cars out of the snow and I need to know some info on this trans. that way I can know when I should be careful about what limits I can push this transmission to.
@ Vinnie, here is a link to the hydro-gear specs for your transmission<code> ;http://www.sauerbibus.de/fileadmin/user_upload/Produkte/Hydro-Gear/PDF/Hydro_Gear_G700_Serie.pdf</code>
Pulling a thousand lbs is not an issue for this trans. With a 1 inch axle it can easily handle 750 lbs of down force on the axles so pulling that heavy of a load is fine. 20 to 23 inch tires are the recommended range and you can go as wide as you want. Keep in mind that putting duel tires on it will put stress on the wheel hubs and I have seen hubs break from the extra stress (but the trans has held up well)
In my opinion the limit to this unit is the drive belt, not the trans. While the belt is a power rated belt, it does wear out over time and could snap if you regularly pull heavy "sticky" loads like logs. I would keep a spare hanging on the wall if you depend on the Garden tractor to work when you need it to.
This site is great and thank for all the advice. I am currently looking at either a manual or automatic transmission model, but wondering about the reliability and maintainability aspects of the two compare. Not planning on using a tractor for ground type equipment, but possibly for carts, etc for a large flat open lawn. Any recommendations for a new kid on the block?
@Zack,
I will always recommend a pedal control Hydrostatic Transmission over a manual or an “automatic” for the new kid. (Sometimes called a automatic hydrostatic)
Why,
1. A foot control “hydro” is the easiest to use. On the right side of the tractor you push on the big pedal to go forward and push on the little pedal to go backwards. Maintenance-wise the hydro is the most dependable. The belt from the engine to the transmission is always at the proper tension and usually lasts for years.
Safety-wise the hydro is the easiest to learn and if you get in trouble just lift your foot off the pedal and the tractor will stop. The hydro also has “built in” braking. Under most conditions the transmission will hold the tractor in position without having to step on the brake. (Always set the parking brake when you get off the tractor though. It is normal for these transmissions to slowly creep (move forward or backwards) if left unattended.
2. A fender control hydro is just as dependable, but it takes a little more practice to drive. You use your right hand to set the speed of your tractor, to stop the tractor and to make the tractor to go in reverse.
3. An “automatic” transmission on the gray Craftsmans is a variable speed belt drive. The ground speed is controlled by your right hand and the forward/reverse is control with your left hand. You usually set the ground speed and then “shuttle” tractor forward and reverse as you mow. The “automatic” has two belts and if you ever use your tractor to pull heavier loads (like loads of dirt in your cart) you will wear out these belts. The tractor eventually will go slower than normal or slow to a stop going up a slope. You will have to change these belts more often than the one belt in the hydro model. I have had belts last 10 years in “normal” use and I have destroyed the belts in as little as a day trying to pull loads of dirt.
4. Manual transmissions today do not have a clutch like a car or truck has. They use the belt tensioner from the engine to the transmission to start and stop the tractor. When you engage the clutch (lift your foot off the clutch with the transmission in gear) you are just tightening the belt tensioner. The problem is it is almost an on/off type of device. The “clutch” is either engaged or disengaged. This tends to make the tractor “jump” when you left out the clutch and I have a lot of people complaining about how jerky this is. If you have the transmission in 4 or 5 and the engine at mowing rpm many times you can pick the front wheels off the ground when you let out on the clutch. It takes some practice to start and stop a manual transmission tractor.
What else would you like to know?
Thanks Paul! You answered all my questions. Understand your description of the manual drive train and see they all use belts, but is just a matter of how they are engaged. I’ll leave comments on my “new to me” home owner purchase. Thanks again, Zack
I ended up with the hydrostatic – it's great. Went the whole summer with no issues. If you have hilly property a manual tranny might make sense as the hydrostatic doesn't have any "engine braking" so it speeds up some when you go down a hill. It takes a little getting used if it's hilly to but overall it's been a great mower – no issues.
I have a 15 horse hydrostatic drive craftsman lawn tractor.
I have had it about 9 yrs. The transmission wears out after about 4 years of use. I plow my drive in winter and my yard is on a hill so I use the transmission heavily.I need to rebuild the transmission again but think I would be better off buying
a tractor that will hold up to the hill and snow removal. Is this a common complaint and what tranny do I need. Shifting gears on a hill is tough. I like the hydrostatic but it wears out fast.
@ Michael,
This is not a common problem. In fact the Sears Service Techs feel the hydro is stronger and will hold up better than the manual trans.
I suggest you look at the <code>GT 5000</code> It has a heavy-duty hydrostatic transmission. Sears calls this heavy duty unit a "Premium Hydrostatic Transmission"
@joebillybob, The Sears service techs tell me the hydrostatic trans have the least repairs. The belt that drives the hydro also lasts longer than the one for the manual trans.
But, the manual is usually 200 to 300 dollars less so you can buy a lot of belts over the life of the mower for that.
I personally like the fender hydro controls because my foot gets cramps using the foot controls for a long time. But the hydros with foot controls on all the Craftsman mowers comes with cruise control and drives very similar to a car so many people like that.
That said, if you have a lot of landscaping to mow around the hydro is easiest to drive. If you have large open areas to mow the cheaper manual works just as well because you just put it in a gear and go…go…go
Your site was very helpful, thanks. One question re: transmissions. I'm going to buy a YT3000 and am trying to decide between the 6 speed and the hydrostatic. Many years ago I used a JD 212 w/ a 4spd manual and the manual suited me fine. Durability wise which type would you recommend?
thx.
JoeBillyBob,
What did you decided on? I am trying to make the same decision…it seems the hydrostatic would be easier cutting the grass. This will be my first yard tractor…and my yard is relatively flat with a small drainage ditch and some trees to go around. However, the 6 speed is a lettle less expensive and I understand repair bills are usually lower.
Thoughts?