Hydrostatic Transmission - Transmission
Sundstrand Hydro Transmission - Rebuild and Repair
are offering a rare service - rebuilding your hydrostatic
transmission and or differential. Most parts are already in
stock. The complete drive line units in the following tractors
can be repaired or rebuilt:
Hydrostatic Transmission Troubleshooting Q&A
John Deere 110
John Deere 317
John Deere F911
John Deere 112
John Deere 318
John Deere F912
John Deere 120
John Deere 322
John Deere F915
John Deere 140
John Deere 332
John Deere F925
John Deere 300
John Deere 400
John Deere F935
John Deere 312
John Deere 420
John Deere F932
John Deere 314
John Deere 430
John Deere F1145
John Deere 316
John Deere F910
included are the older International Cub
Cadet garden tractors,
Allis Chalmers garden
tractors, and Ariens garden
tractors. with a Sundstrand hydrostatic
Nothing makes us feel more satisfied
than to take good solid equipment that is serving our needs well and
fixing it up if it has quit, or improving it's performance.
Some equipment is "throw away" not worth fixing, but most of us have
garden tractors that can outlive us if we take good care of them.
We don't baby our own equipment, we work it hard. If you have
well built equipment it would be money well spent to rebuild or
repair your hydrostatic transmission rather than buy something new
that probably is not as sturdy.
If you would like to have your hydro rebuilt give us a call:
or e-mail us:
We can give you an approximate cost
for the hydro rebuild and help you decide if your hydro is worth
rebuilding. You ship the hydrostatic transmission to us,
we rebuild it, and ship it back to you, usually FedEx Ground.
It is never a good idea to tow a tractor with a hydrostatic
transmission. Many of the tractors that come to our shop
needing transmission work, need repairs because the tractor has been
towed. If we have to move a tractor with a hydrostatic transmission
that has broken down we will even just skid it, yes hard on the
tires, rather than ruin an expensive hydrostatic transmission.
Q: I have a Jacobsen 1450
Superchief garden tractor with a hydro transmission, but I'm having a problem
with it. The hydro transmission doesn't work, no reverse, no front drive at
all, but when I got the back wheels off ground and I engage the transmission,
the wheels move and the tranny seems to work, forward and backwards. I can
hold the wheels from turning around with just my hands. There are no rattles
or weird noises from the tranny whatsoever. There are no oil leaks except one
that could be caused by a worn rubber seal, or the nut that holds the seal,
that isn't tightened up properly. The manufacturer of the transmission is Hydrogear.
The lawnmower is a project I bought a few days ago but by the looks of it it
has been a long time since it's last been used, I guess a year or 5, maybe
even longer. I hope that you can give me a clue of what's wrong with it.
Take your charge pump apart and see if
the drive pin is sheared off inside the pump.
Q: I just had the Sundstrand
hydrostatic transmission on my 1973 Wheel Horse Model # 10440-8
replaced. The replacement was an old unit out of a similar Wheel
Horse tractor but the mechanic said that it looked good enough to
The tractor works ok until it warms up (after about an half hour to
an hour of use) and at that point it slowly looses all power until
it finally will not go all. As soon as it cools down it runs ok. All
fluid levels are at the proper levels and there has been no loss of
transmission oil. There is, however, a slight film of oil on the
bottom of the rear of the tractor but none at the gaskets of the
Any thoughts as to what is wrong and does the unit need rebuilding?
Any time I hear about a hydro slowing
down more and more as the oil gets warmer and warmer, it tells me
that oil is bypassing internally and that calls for a complete hydro
Q: I was given a rough 300
John Deere lawn tractor but it has a blown engine. I will most
likely get a
Re-power set up from you when the
time comes. I want to go through this thing and check everything
else out but need to move it first. How do I disengage the rear
differential so it can be pulled or moved?
Screw down that knob between your
legs. Do not push it fast or far, as you will damage a good
hydrostatic transmission. Sure, let me know when you're ready to
repower your John Deere 300.
Q: I have an older, belt
driven John Deere 214 garden tractor. I was recently using it to
plow snow when it jumped out of gear and I attempted to put it in
neutral. When I let off the clutch it would go forward. I could not
get it to go in neutral. Then I put it in 3rd gear and the engine
nearly locked up and it stalled. I restarted it and put it in third
gear a second time and when I let off the clutch it did the same
thing but the (I think) drive pulley broke off. Can you tell me what
the problem would be and what I need to fix it?
I hope you are correct that you broke
your drive pulley and that you did not blow up the transmission. If
you did not already blow up the transmission, take your shift tower
off and take a pry bar and align up those 2 sliding rods in the
transmission. If you cannot get it to work you will have to have it
Q: My 1973
John Deere 140 H3 has been sitting
for a year. I did a head gasket today, new carb, new coil, and new
points. I got it running great. I push the stick forward and have
nothing! I have full power backwards, the deck lift works fine, but
no forward. It has fluid in it, and it's not whining, and the
linkage looks okay underneath. How can I have everything else, but
no forward? We have had no issues in 33 years with this tranny.
Please tell me I am missing something easy.
It sounds like one of your
control valves are stuck open on top of your hydro transmission. To
check this you would have to remove your rear fenders and check the
Q: I have a
Cub Cadet 2084 Super Garden tractor
rand I have a few concerns about my hydrostatic transmission. My
tractor seems to be jerky when I go from forward to reverse and it
doesn't have much power in reverse. My father could not get it
started one day and he pushed it from the front of the garage to the
back of the garage about 25 ft, could that have possibly damaged the
transmission? If a transmission gets damaged in this manner what
kind of symptoms would it exhibit?
I would say he did not damage the transmission just by pushing it
only. If you would have said be hooked onto it with something else
then I would have been worried. Sounds like you need to replace some
of your external linkage and also adjust the hydro after you have
things replaced. If this doesn't take care of your problem you may
need a overhaul.
Q: I have a transmission
problem in my John Deere 316 garden tractor. The forward-reverse
lever moves only part way up or back allowing only minimal movement
of the tractor. The deck hydraulics seem to work fine, however I
notice the fluid level is not in the viewing glass as it should be
or is it even moving in the lower tube as it is clear. I have
drained the fluid and refilled but
still the same result. Any suggestions?
A: It sounds like there
is nothing wrong with your hydro transmission. You need to replace
some of your hydro linkage that is worn so you do not have all that
play in the linkage.
Q: I have a 15 HP Z-Force 44
Cub Cadet Riding mower and it just
started having a problem turning the left back tire. The tire will
rotate but it seems the pump is not working properly. It just makes
a loud growl and barely moves the tire. Is my hydrostatic pump going
out or is their a problem elsewhere?
A: It sounds to me
like the hydrostatic transmission is going out or if this unit has
hydraulic driven motors on it, they are going out.
Q: I have a John Deere 175
Lawn tractor with a hydrostatic transmission. When cutting it gets
hot and doesn't want to pull, how can I fix this?
The first thing to check would be the
condition of the drive belt, if it is tight on the pulleys. After
this it sounds like you will need to get a different transmission.
Back to top
Q: I have a John Deere G100 lawn tractor that won't move over 30
yards without stopping and making a noise. Do you think I may need a
new hydrostatic transmission?
You could change the oil and filter if you have one
and see if that takes care of your problem. It it does not, you can
check with me and I will check into it to getting you a new
Q: I have a
Bobcat T-20 Lawn mower manufactured
by Wisconsin Marine, Inc. about 30 years ago. It is still in good
operating condition. It has a Sundstrand Model 15 hydrostatic
transmission. How often should I change the oil and filter in the
Q: I have a problem with a John Deere 316 hydrostatic lawn
tractor I'm restoring and I would deeply appreciate your opinion as
to what the problem may be. I have been in the automotive business
for the last 40 years and lawn tractors are not my specialty. The
problem is with a high pitch whine when the tractor is going up hill
progressively getting louder as the speed picks up but the whine
dies down when going down hill. The transmission works perfectly all
but for the rather loud whining. I set the neutral position and
there is no creeping in forward or reverse. I changed the
hydrostatic oil and used F type which the service manual suggested.
The filter does not seem to be that old, but no difference was
noticed. I would appreciate any suggestions you may have.
A: John Deere has 3 model 316
garden tractors, the 1978 316 with
a 16 horsepower 1 cylinder Kohler engine, a 1983 to 1986 316 with a
16 horsepower Onan engine, and a 1987 to 1992 316 with an 18
horsepower Onan engine. It is normal that they will do this
sometimes. We have run them like this and everything stayed
together. If you have the transmission overhauled it might take care
of the noise but as long as it is all working fine, just run it.
The book will say 1 year or 500
hours, whichever comes first.
Q: I have an old
Simplicity 4041 that I'm having
trouble with the hydro. transmission. The unit in my tractor is a
Sundstrand unit model # 90-1113. I have the unit pulled out and
think the problem is in the unit itself. I would love to have a
schematic of that unit before taking it apart. It seems like the
lever that the linkage hooks up to is loose and sloppy. Do you know
anything about this unit that might help me before I take it apart?
Can I still get parts for it? And if needed, can you rebuild this
Also, I have heard of replacing my Onan with the Vanguard engine.
This is something I will need to take a look at pretty soon. My
Onan's getting tired. Do you have a
conversion kit you sell for that?
A: Yes I should
still be able to get parts for you. I can rebuild the hydro for you
if you decide to do so.
I do have the
Vanguard engines in stock if you
get to deciding to go into a real smooth quiet running package.
Q: How does one
tell if the free wheeling valve on a John Deere 420 is working or
not? I have turned it out and back in several times but the wheels
seem to move freely for a short distance then seem to catch?
A: You should not tow these transmissions as you can
cause damage internally. I am assuming this is a tractor below the
30,000 serial number. This free wheeling valve should be turned all
the way in clockwise and this would be ready for tractor usage. If
you are having trouble with the tractor not working correctly, then
it does sound like a hydrostatic transmission problem.
Q: I have an F910 with a
hydrostatic transmission problem, here are the details:
Reverse is really slow and it seems to get stuck in between forward
and reverse, makes lots of noise and shakes. Is there a linkage
adjustment or anything I can do? Or is this typical to a hydro
A: You should check out the external linkage on the
outside of the hydrostatic transmission and make sure that is all
O.K. before we condemn the transmission. Repair any and all slop
that is in the linkage, then if problems are still there we will
need to get into the transmission overhaul subject.
Q: I have a small
problem with my hydro unit on my 1970 127 Cub Cadet. When I come up
to any kind of uphill grade, or a hard pull mowing grass, sometimes
it seems like my hydro is slipping, and I have to move the lever
more to keep it moving, and when I am out of the hard pull, it seems
to speed up. Do I need a rebuild? I have to add that I have several
John Deere hydros, and I do not have this problem. Also, is it
possible to put a three point hitch, and a rear PTO on my John Deere
314, to maybe run a small finish mower?
A: Yes, you are correct, your hydro transmission is played out and
definitely needs rebuilding. We would do a complete overhaul on it.
You can put a 3 point on your John Deere 314 but they are very hard
to find and pretty expensive.
Back to top
Q: I have a John Deere
300 that I purchased this fall and I have a question. I don't know
if it is a transmission thing or what. I understand that when you
want to turn short, you put on the brake on one side and then turn
that way. that is not the case with my tractor. When you are pulling
something really heavy , both rear wheels will spin at the same
time, not one and then use the brake, and the other will pull. Is
there a differential lock or something on this tractor that makes it
act this way? The hydrostatic transmission works great
otherwise--holds back on hill as it is supposed to do and all that
good stuff--no leaks--.
A: No, there is no differential lock on that tractor. when
you are pulling a heavy load both wheels should spin at the same
time if the traction is equal. Just say if you are pulling a load
and one wheel gets on ice and the other one on dry ground, the one
on ice will spin and the tractor will probably be sitting still and
not moving. Then if you would step on the brake of the wheel that is
spinning on ice, the tractor will start and continue to move until
you passed over the ice and then you can release the brake and
continue on your way.
Q: I have a 1992 John
Deere 318 with hydrostatic drive for lawn mowing, snow removal, an
all around work in the woods and property. I recently developed a
problem with a leak in the hydro unit at the input bearing off the
tractor's drive shaft. Upon closer inspection I discovered that the
tractor had a broken rear axle mount on the left side of the tractor
and the axle had slipped rearward throwing the torque off center. In
checking with John Deere and a local hydraulic repair shop the
repair would appear to be worth more than the tractor's worth. The
hydro unit I was told, is a Sundstrand 90 series, and the repair
would include the bearings, seals, new drive shaft to replace the
scored one, and a new pre pump which they say was damaged by the
shaft riding off center . The repairs would come to about $1000.00,
and a replacement pump about $1100.00 to $1200 with me doing the
I wanted to know several things before proceeding with this project.
First, does this sound reasonable to repair or replace the hydro
unit, if indeed it's worth doing in the first place, or do you think
there is a less expensive approach? Secondly do you perhaps have a
source for replacement pumps at a more reasonable price? I'm not
sure it's worth putting this much value into a tractor that is this
old, or would I be better off not repairing it? The tractor itself
is in very good condition except for the hydro unit and I need
something to continue with snow removal and working in my woods. I
use the tractor to maintain woods trails, and haul firewood up to
the house using a small two wheel utility cart. My last question to
you would be for a recommendation on a replacement tractor which is
more like a utility tractor, for the way I use my equipment. The
John Deere dealership has a used 855 with a front loader coming in
on trade for around $11,000 (more than I'd like to spend) but maybe
that's the kind of tractor I need for the projects I want it to do.
You seem to really know this equipment and I'd appreciate some
guidance in this matter if you have the time.
A: You are working with a very dependable garden tractor. We
do transmission overhauls and most times feel it's a wise investment
if the parts are available. You can not really blame the tractor for
what happened in your situation. I think that tractor is well worth
fixing. If you bought a new one of the same quality you would have
to buy a X model for about $8000. That 855 is nice but it still is a
bigger, clumsier tractor and those
John Deere 318's are by no means
little babies. They will do some serious work. Just weigh them down
and the fun really starts.
Back to top