Hydrostatic transmission slipping when hot

Is your transmission experiencing a loss of power? Diagnosing this issue can be a daunting task. As always, we recommend seeking the expert opinion of your local service dealer; however, if you want to address the issue yourself, here is some helpful information. In the majority of cases, power loss can be traced to one root cause, the cylinder blocks and the center case need to be replaced. If you plan to repair this issue, it is critical to replace all components.

This would include two cylinder block assemblies with new pistons and springs and the center case. If the cylinder blocks or the center case has damage due to wear, then the related parts will also require replacement. If all parts are not replaced, it is very likely that you will have another failure within a short time.

There are many misguided blogs on the internet that say you can save money by not replacing all components. This may be true in the short term; however, it will drastically shorten the life of the parts and likely cause a situation for additional repairs.

In this scenario, we have found that future repairs require replacing all related components. To that end, we offer a complete repair kit that includes the center case, cylinder block assemblies, gaskets, filters, and sealant. Our genuine Tuff Torq replacement kit is available on our service website, here. We are always happy to answer your questions. Please email our service team here or by phone at Your email address will not be published.

I have a small shop and repaired mowers and trans. Customer said when pushing the paddle to go forward makes a loud grinding sound, also reverse. Have the trans split. Hello, I would inspect the linkages first. Then the pulley and the input shaft. If everything with those two areas are ok then you want to open it up. Hello, You can try changing the oil and seeing if it helps.

hydrostatic transmission slipping when hot

Goes great uphlll untill hot, then only goes up same hill backwards while still hot. I have Husqvarna yth with k I tried towing too much weight and the transmission gave out. I bled the system as indicated in Husqvarna manual by raising off ground and cycling between forward and reverse, then repeating while on the ground.Buying Advice.

Pro Talk. Photos New media New comments Search media. Log in Register. Search titles only. Search Advanced search…. Today's Posts. Unread Posts. Search forums. Log in. JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding. Thread starter xray man Start date Jun 3, Joined Sep 2, Threads 3 Messages 8. Transmission would slip after it got hot, no reverse.

hydrostatic transmission slipping when hot

Worked after cooling off. I had heard that trans wasn't serviceable. Found a YouTube video that said otherwise. Removed transmission, drained it ,seperated case- all gears looked good, no metal shavings, just very fine metal stuck to magnet. I might have just been lucky that fixed it but I ain't proud.

It would have been a pisser to junk the mower because it needed a transmission. I imagine there's been a lot of them junked because the transmission took a dump and folks thought they couldn't be fixed. Anyhow, thought I'd throw that out there in case somebody runs into the same problem. But I got out of that ditch and slid in another one. See my next post please. Need some advice. Joined Jun 15, Threads 1 Messages 4. Good info, thanks. I am thinking about buying a used K46 for my L just to go through and keep as a spare as I hear they all end up in the same basket at some point or another.

Thanks again!

Hydrostatic Drive Loader Doesn't Drive When Warm

Joined Nov 29, Threads 32 Messages 14, You must log in or register to reply here.According to the experts at Today's Mower, there are fives types of drive gear in common use on lawn care machinery: gear, friction disk, automatic, CVT, and hydrostatic. Hydrostatic drives are extremely easy to use when compared to geared versions; with the latter, the operator usually has to come to a complete stop and depress a clutch to change ratios, which becomes tiresome for people using such machines professionally.

Hydrostatic drives have no clutch and offer infinite speed variations. They even shift from forward to reverse with a simple change in pressure on one foot peddle. That said, there are a number of ways in which they can fail. All five drive types have certain components in common, and the failure of any of these can result in the lawnmower not moving. Most manufacturers install a pressure-sensitive switch under the seat to interrupt the mower's self-propulsion when the seat is unoccupied; a defective switch can result in the drive not being engaged.

A seized-on parking brake can either render the mower immobile or reduce its performance significantly. All drive types must be connected at some point to the motor, so there must be a cogged or splined power take-off; stripped cogs or splines will not transmit power to the drive. Hydrostatic transmissions -- often referred to simply as hydros, hydro-drives or HSTs -- are constantly variable drives similar in operation to car automatic transmissions.

They have a pump that effects hydraulic fluid inside a closed system, and reduction gearing that responds to changes in that hydraulic pressure. Mechanical components also include a differential and a drive axle. Failure of any one of these components will prevent the lawnmower from moving. Hydraulic fluid is passed through either high-pressure rubber or metal hoses; a leak from the hoses or any of the other components will also stop the hydrostatic transmission from working.

By far, the most common reason for hydrostatic transmission failure is old hydraulic fluid. John Deere states that "Operating outside of the recommended oil air temperature range may cause premature hydrostatic transmission failure. This decay results in air and atmospheric moisture becoming blended into the oil, properly called entraining. Oil that is entrained has inferior hydraulic properties in comparison to fresh oil, resulting in less than optimal system function. Entrained oil must be drained completely.

After positioning the lawnmower to drain properly -- typically this means on a perfectly flat, level surface -- remove the drain plug and allow the machine to stand for several days until every last vestige of the old oil has dripped out. Only use replacement oil of a type recommended by the mower manufacturer. John Deere advises against using red "Type F" automatic transmission fluid and bio-based oils.

Most manufacturers recommend SAE 20W hydraulic fluid. John Cagney Nash began composing press releases and event reviews for British nightclubs in His material was first published in the "Eastern Daily Press. In he earned an OxBridge doctorate in philosophy and immediately emigrated to America. By John Cagney Nash. Hunker may earn compensation through affiliate links in this story.

Hydrostatic transmissions are common on ride-on lawn care equipment. John Cagney Nash. Show Comments.Forum Rules. This website or its third-party tools process personal data e. To learn more, please refer to the cookie policy. In case of sale of your personal information, you may opt out by sending us an email via our Contact Us page. To find out more about the categories of personal information collected and the purposes for which such information will be used, please refer to our privacy policy.

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Understanding and Troubleshooting Hydrostatic Systems

Since I am looking for information on a mechanical component, it may be of interest to some. I recently bought a new to me Simplicity broadmood lawn mower in beautiful condition. The wife has given me much heat about it cause it will not climb a hill. I changed the oil in the hydro unit and it is more quiet, but still is slipping internally. It is a hydro gear unit.

There is no drain so I sucked the fluid out and refilled. I can dis assemble anything and if I spot a problem, I can secure parts and repair. I can not afford to get a rebuilt unit. I have searched the net for days and have not found anything other than a parts list. Does anyone here have advice on saving face with my family?Husqvarna riding lawn mowers have a sealed transaxle or transmission and do not require fluid monitoring. When you purchase a new Husqvarna riding lawn mower or have a new transmission installed, however, purge the transmission to release air within the system.

Air enters the system during shipping and when the transmission is replaced. Air in the system affects the supply of power to the lawn mower's wheels for forward and reverse movement. Raise the Husqvarna lawn mower's attachment lift lever on the left side of the operator's seat to the highest position. Walk to the rear of the lawn mower, and pull the freewheel control outward and down, locking the transmission in the disengaged position.

Push the lawn mower to a flat, open area of your lawn. Sit in the operator's seat. Press the brake pedal forward with your left foot to engage the brake, and hold the brake pedal in that position. Push in the attachment clutch switch on the right side of the dash to disengage the cutting blades. Push the throttle control on the left side of the dash upward to the fast setting, and pull out the choke below it to engage it. Insert and turn the ignition key to the right, and immediately release it when the engine starts.

Push the throttle control down to the slow position. Place the motion control lever on the right side of the seat in the center, neutral position. Move the motion control lever upward to "Forward" for five seconds.

hydrostatic transmission slipping when hot

Move the motion control lever down to "Reverse," and hold it there for five seconds. Repeat this procedure an additional three times. Move the motion control lever to the middle, neutral position, and turn off the engine by turning the ignition key. Walk to the rear of the lawn mower. Lift the freewheel control, and push it inward to engage the transmission.

Start the engine, and move the throttle to about one-half speed.

How to Purge a Husqvarna Lawn Mower Transmission

Move the motion control lever to "Forward," and drive about 5 feet. Move the motion control lever to "Reverse," and drive about 5 feet. Move the control lever to the center, neutral position. Repeat the forward-reverse-neutral process three additional times. Mary Lougee has been writing for over 10 years. She holds a Bachelor's Degree with a major in Management and a double minor in accounting and computer science.

How to Troubleshoot the Hydrostatic Transmission in a Cub Cadet

She loves writing about careers for busy families as well as family oriented planning, meals and activities for all ages. By Mary Lougee. Photo Credits. About the Author. How to Use a Rear Mount Tiller.Purchasing a lawn tractor with a hydrostatic transmission represents a significant financial investment for most homeowners, so it can be particularly frustrating when you experience trouble shifting the machine.

Hydrostatic transmissions, unlike those that contain traditional manual or automatic transmissions, use an oil-filled hydraulic pump to control the mower's speed and direction. When shifting problems occur, it's crucial to repair them quickly so you're able to use the tractor in the most effective manner.

When it comes to shifting and directing the lawn tractor, hydrostatic transmissions rise head and shoulders above other types of transmissions.

On a hydrostatic model, you'll never encounter grinding or stuck gears because there are no gears to grind. You also do not need to stop the mower to shift it into another gear to slow or speed up the machine.

Simply use the hydrostatic controls to make the change while you're still in motion. Although mechanical problems with hydrostatic transmissions are rare, they do occur occasionally. A leak of the oil that powers the hydraulic pump will reduce the internal pressure and can cause difficulty in shifting.

You may notice the lawn tractor simply doesn't have the power it had previously or doesn't respond to your shifting. It's also is possible the transmission control arm may be out of adjustment, affecting its performance when you shift the machine. If the tractor's wheels continue to move when the machine is in neutral, it's time to access and adjust the adjustment bolt.

When there is no response to your movement of the shift control arm, you may have activated the manual bypass lever. Useful for towing or pushing the lawn tractor, the manual bypass lever will stop the tractor from responding when you push the control arm until you disengage the lever. If you're new to using a hydrostatic tractor, simple operator errors may fool you into thinking you have a shifting problem. Before you jump to conclusions, ensure you've released the parking brake before shifting the machine or the tractor will not respond to your adjustment of the control lever to move forward or backward.

Trying to shift while using the cruise control feature may also make it appear there's a shifting problem. As long as the machine is in cruise control mode, you will be unable to shift to a higher or lower speed; disengage the cruise control before attempting to shift. Since most hydrostatic transmissions are completely sealed within a steel or metal casing, they aren't accessible to the user when it comes to repairs.

Rather than risk voiding the warranty that came with the lawn tractor by attempting to work on the hydrostatic transmission yourself, seek out an authorized service representative to perform diagnostics or make repairs.

Troubleshooting and repairing a hydrostatic transmission is beyond the scope of the average homeowner, who likely doesn't have the appropriate tools, training or knowledge for the job. Amie Taylor has been a writer since Book reviews, gardening and outdoor lawn equipment repair articles and short fiction account for a handful of her published works.

Taylor gained her gardening and outdoor equipment repair experience from working in the landscaping and lawn-care business she and her husband own and operate. By Amie Taylor. Benefits of Hydrostatic Transmissions When it comes to shifting and directing the lawn tractor, hydrostatic transmissions rise head and shoulders above other types of transmissions.

Potential Problems Although mechanical problems with hydrostatic transmissions are rare, they do occur occasionally. Operator Error If you're new to using a hydrostatic tractor, simple operator errors may fool you into thinking you have a shifting problem. Hydrostatic Transmission Repairs Since most hydrostatic transmissions are completely sealed within a steel or metal casing, they aren't accessible to the user when it comes to repairs. Photo Credits. About the Author.

How Do Hydrostatic Lawnmowers Work?Friction creates heat. Fluid under pressure, being forced through restrictions, is subject to friction losses and pressure losses, generating heat as a by-product.

All the moving parts also are subject to friction losses, which also generate heat. The heat you feel is directly related to the efficiency losses in the transaxle. Check any filters that may be restricting oil flow to the transaxle. Are any heat exchangers installed in the system?

The heat can also be created from the transaxle being overworked by other components in the system that are not operating properly. Ditto to what RVZ said. I would also add that the units should be kept clean. Dirt and debris stuck to the casing and cooling fins prevent heat from being transferred away. The design of the machine the hydros were put into can also be a factor.

In other words, is the machine around the hydros designed to provide sufficient air movement and cooling or does it hinder the fan's performance. Keep in mind that if this has a lot of hours on it, say more thanthe parts may simply be getting worn. Depending on the application, those units can have design lives of anywhere from to hours.

Even though the parts look good, they may be worn past their optimal tolerances. There may be some seals that are worn as well.

What Makes a Hydrostatic Lawnmower Not Move?

Between the hydraulic components and the mechanical components, the efficiency losses are enough to noticably affect the performance. The greater the inefficiencies, the greater the heat buildup. On the plus side, the unit is probably rebuildable. Hydrostatic transmissions tend to be very inefficient. Back in the 's I tested a variety of hydrostatic transmissions for lawn tractors as GM was looking to put a hydrostatic transmission in a Cadilac.

That means a lot of heat is produced when operating a hydrostatic transmission, especially when operating at a high reduction ratio. Since you mainly use the mower in hot weather, if it was my unit, I would fill the transmission with 10W40 or 20W50 Multi Viscosithy Engine oil when you put it back together. Engine oil is designed to operate at elevated temperature and the Multi Viscosity stuff does'nt thin out so the efficiency stays up as heat builds.

Even Vickers and Eaton recommend Engine oil as a suitable replacement for Hydraulic oil and several mobile equipment operators locally use engine oil in all their hydraulic circuits to eliminate the chance of someone putting the wrong oil in the wrong equipment. I would be cautious about putting an entirely different type of oil in the transmission. It may perform better for a while if it is all worn out inside, but unless the oil is recommended, I wouldn't do it unless you just want to get by for a while longer before replacing the entire unit.

No offense, but I would regard Bud's tip as a last resort before having to replace the unit, although it may be enough to get you by until a more opportune time for replacement. Another resource you might check is www. There is a mechanics forum on there where there are a lot more people that have actually worked on these things than probably what you'll find here.

There are a lot of good people there too. Hey, good for you.

hydrostatic transmission slipping when hot

The grass must be quite high by now.


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