Fix Your Hydrostatic Transmission Problems Fast

i'm caleb bragg and today we're going to discuss some common issues with hydrostatic transmissions hydrostatic transmissions are found in various types of equipment ranging from lawn mowers to mid-sized tractors in order to diagnose any issue you really need to know how the system works when it is not giving trouble here's a simple breakdown of how a hydrostatic transmission works the transmission input shaft is most often turned by a belt on a lawn mower and is shaft driven on tractors the transmission input shaft is directly splined to the transmission pump in some cases a charge pump will provide a small amount of oil to the transmission pump to prevent the cavitation of the oil in a one-speed pump the pumping unit is comprised of a rotating group of pistons that are riding against a fixed plate that engages the pistons as they turn the rotation of the rotating group against the angled plate caused the spring-loaded pistons to extend and retract based on their position on the plate this action pressurizes the oil the pressurized oil then flows through a manifold block over to another rotating group of pistons called the hydrostatic motor this unit has a variable swash plate that means you can manipulate the angle at which the rotating group of pistons is engaged the more angle that is put on the swashplate the more oil flows through the motor this is performed by pushing further on the drive pedal and that is why you go faster when moving the pedal more the motor is splined to an output shaft which then will drive the gear section of the transmission through gear reduction your axles are then turned so now that we have a general idea of how it should work we have a better idea of what could be going wrong when there is a problem for example you are mowing grass and everything's going great when all of a sudden your mower quits moving the first step you should take is to shut off the mower and put on the parking brake if you have some gloves in the toolbox put them on so you don't burn yourself then lower your deck so you can see your transmission drive belt make sure it is on all of the pulleys there should be slack in the belt if the parking brake is engaged it will only be tight when you let off the pedal look for sticks or other debris sticks are the number one cause of loss of drive if you see debris clear it out and make sure to reinstall the belt if it's not damaged let's say there's no debris and the belt is in place if the transmission hasn't been getting weak over the last few weeks or months then it is very likely that the drive pulley located on the transmission input shaft has stripped out this pulley is made of a softer material than the input shaft and the splines will wear out over time so the pulley may be turning but the input shaft is not in this case you will need a 30 or 40 dollar pulley and a few hand tools you'll be back in business in no time some models allow you to add or even change transmission oil and others don't if you have the ability to check your transmission off then check the oil level in this case you can try changing your transmission oil and filter if you cannot service your transmission and the first two scenarios didn't help then you may need to change your transmission usually when your transmission will need replaced it has given you some warning typically the lawnmower will have trouble going up hills or will seem much stronger when the oil is cold that's because oil fins as it heats up and the hydrostatic transmission pump can't build the needed pressure to turn the motor this happens more in hilly terrain than on flatter areas but before spending a ton of money on a new transmission contact your local dealer and have them take a look at what could be going on be sure to include as much information as possible concerning the terrain in which you operate and fully describe what was going on when the failure occurred let them know if it has seemed weak over the past few months or so these details will help the technician more quickly diagnose the issue and get you back to mowing more quickly thank you once again for tuning in and i hope this video will help you the next time you find yourself in a bind feel free to check us out on the web at www.nelsontractorco.com or give us a call toll free at [Music] 877-788-0413

Channel: Nelson Tractor Company

Views: 58,442

Rating: 4.3832598 out of 5

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Id: nFKBvMo0pS4

Length: 4min 8sec (248 seconds)

Published: Tue Sep 15 2020