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Hydrostatic Transaxles on everyday riding lawn mowers

#1

4

4950cycle

Hi, I'm a newbie here , I notice a lot of riding lawn mowers boast "Hydrostatic Transaxles". But all the riding lawnmowers I've ever worked on have what looks to me is all direct mechanical drive componants variable pulleys, internal gears and such . I've noticed no fluid drive hoses or seals. And have opened them up to replace worn out axle gears and such only to find a gear box full of nothing but grease. Whats Hydro about it ? How do they get away with this boloney ? :rolleyes:


#2

R

Rivets

I suggest you haven't been around for a while. Goggle these manufacturers and you will see what a Hydrostatic Transaxle is. Torq Tuff, Peerless, HydroGear, Spicer/Dana. Take part one of these and the only gears you will see are those which make up the differential. This is no baloney to those of us who repair them, there is a big difference between a six speed gear transmission and a hydrostatic transaxle.


#3

4

4950cycle

Will do Rivets


#4

S

sgmgarden

Welcome to the forum :smile:


#5

Carscw

Carscw

4950cycle said:
Hi, I'm a newbie here , I notice a lot of riding lawn mowers boast "Hydrostatic Transaxles". But all the riding lawnmowers I've ever worked on have what looks to me is all direct mechanical drive componants variable pulleys, internal gears and such . I've noticed no fluid drive hoses or seals. And have opened them up to replace worn out axle gears and such only to find a gear box full of nothing but grease. Whats Hydro about it ? How do they get away with this boloney ? :rolleyes:
Click to expand...

I understand your thinking.
We see the word hydro and think there is a pump with hoses going to a motor.

Like a car has a hydromatic tranny

(( cowboy up and get over it ))


#6

4

4950cycle

Than where does the " fluid " come into the picture ? I'm almost sure where motorized machanics comes in Hydro usually means something is hydrolic about it. Unless this is just a word used to marketing them ? I just see a pulley driven simple little muti speed non-synchronized gearbox. Unless I just haven't run into the certain fluid drive type yet ? But don't they call all these riding lawn mower transaxles Hydrostatic ?


#7

Carscw

Carscw

4950cycle said:
Than where does the " fluid " come into the picture ? I'm almost sure where motorized machanics comes in Hydro usually means something is hydrolic about it. Unless this is just a word used to marketing them ? I just see a pulley driven simple little muti speed non-synchronized gearbox. Unless I just haven't run into the certain fluid drive type yet ? But don't they call all these riding lawn mower transaxles Hydrostatic ?
Click to expand...

Man I wish I could explain it but I can not.
I have taking then apart and like you can not find a reason to call it a hydro.

There are guys that use them on mowers they play in the mud with. They take them apart clean them out and fill with heavy duty grease.

There are a couple guys on here that can explain this to us maybe they will help out.

(( cowboy up and get over it ))


#8

4

4950cycle

Thank you Carscw. There are guys on here that are inferring I have no idea what I'm talking about when I say I see nothing " Hydro " about these lawnmower transaxles. Thanks again for confirming I know what I am looking at Carscw ! :rolleyes: to them that don't know what Hydro refers to when it comes to drive systems.


#9

R

Rivets

I guess you mean me. When talking about hydrostatic drives, I assume you mean drives or units which include a variable pressure pump, some sort of controlled pressure pistons, a relief valve system, a fluid which is used to transfer the energy and hoses connecting this unit to one or more hydraulic motors and/or cylinders, depending on the size, to do work. The pressure pump is powered is powered by either an electric motor or fuel driven engine. Today's tractors, as well as many other pieces of equipment can now use this type of propulsion system, because the technology is available to put all these parts into a unit just a little larger than the old 6-speed geared transmission. In my opinion, that is the reason it can be called a hydrostatic transmission or trans axle. It has all the components, except hoses, of what you are talking about. Some company's (Simplicity, Wheel Horse, etc) even run their power steering and PTO cylinders off the same pump with hoss. Both the same in different size packages.


#10

M

motoman

googling will give most people more than they ever wanted on this topic. Interesting note to me is these transmissions have a traction problem (mine). Ebay is full of used ones. Engineering sites lay out 4 or more varieties of them. Some are servicable. My Craftsman dyt 4000 has worked ok now for 10 years . No maintenance checks in the owners manual. FYI


#11

Carscw

Carscw

I have a full understanding of hydraulics as a have built and operated many sand dredges. I have rebuilt pumps and motors while being broke down in the middle of the chattahoochee river.

I understand how a Chevy 350 hydromatic transmission works.

I do not understand how a mower hydrostatic transmission works with heavy duty grease.

I guess I will sit down and read up on it.

(( cowboy up and get over it ))


#12

Carscw

Carscw

Rivets said:
I guess you mean me. When talking about hydrostatic drives, I assume you mean drives or units which include a variable pressure pump, some sort of controlled pressure pistons, a relief valve system, a fluid which is used to transfer the energy and hoses connecting this unit to one or more hydraulic motors and/or cylinders, depending on the size, to do work. The pressure pump is powered is powered by either an electric motor or fuel driven engine. Today's tractors, as well as many other pieces of equipment can now use this type of propulsion system, because the technology is available to put all these parts into a unit just a little larger than the old 6-speed geared transmission. In my opinion, that is the reason it can be called a hydrostatic transmission or trans axle. It has all the components, except hoses, of what you are talking about. Some company's (Simplicity, Wheel Horse, etc) even run their power steering and PTO cylinders off the same pump with hoss. Both the same in different size packages.
Click to expand...

I never doubted that you knew about how this all works.
Was not question your knowledge on this subject
I am just trying to understand it all.

(( cowboy up and get over it ))


#13

R

Rivets

Never seen one yet with grease in it. Ones I work on have everything from SAE 30 motor oil, multi viscosity oil, hydraulic fluid, or synthetic lube.


#14

4

4950cycle

Point taken Rivets, I guess I have never found one of these yet in riding lawn mowers I've worked on. Never saw anything inside the couple 5 and 6 speed transaxles I've worked on that depends on anything hydrolic to operate. You could put them together bone dry and in my opinion they would work fine barring lubrication. Guess I just havn't ran into one of these hydrostatic transaxles yet. But I thought all these modern day (20 yrs. and newer) Riding lawn mower drive systems were called hydrostatic whether you select your ratio or automatic ? Thank you for the input though.


#15

lawn mower fanatic

lawn mower fanatic

I moved your thread to the General Mower Discussion Forum. :smile:


#16

exotion

exotion

A thought occured to me today. The word static is sometimes used as a synonym to mimic or copy.

So hydrostatic probably meens it is mimicking a hydro transmission. Maybe the way it shifts? The way it feels? Or something like that


#17

Fish

Fish

Much of the problem is just terminology. Transaxle, on the older units were a combo of transmission and differential. The real old differential was separate on the real old
models, and the transmission was up in the tractor frame, the differential was a box mounted on the axle, and a chain connected them.

Then MTD came out with their vari-drive, so the gears {1-7} was accomplished by the two belts and the vari-pulley, like a 10 speed bicycle, and their rear end
is just a differential, with a forward/reverse feature.

Snapper type rear ends came about too, but their gears 1-6 and reverse were accomplished by the drive wheel on that plate on the crankshaft..........

Hydro Trannys, well some are just hydro units attached to a differential, here is a little Hydrogear diddy.....

Hydro-Gear ZT-2800 ZT-3100 Product Presentation (english) - YouTube


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