Hills and Hydrostatic Transmissions

JonathanEngr

New member

Equipment
Kubota 3430 HSTC
Mar 15, 2023
7
0
1
North Carolina, US
Thanks for the advice. I'm going to stop and pick up a new drain pan to use for the hydraulic oil. We have an oil depository at our local convenience center, but I have no idea if they accept hydraulic oil. How do you typically dispose of it?

The manual from Kubotabooks is just awesome. I found all of the maintenance items including the one for changing hydraulic oil on a HST models. I checked under my tractor and all of the plugs and filters it shows in the manual are there. I'll swing by the dealer next Monday to get all of the supplies, and if I have some time on Tuesday I'll change all of the filters and fluid. Once I've done that I'll post back with any changes and/or improvements. I'm not expecting *much* since this behavior has existed since my tractor was completely new, but at least I'll know I'm up-to-date on all of my maintenance.
 

D2Cat

Well-known member
Lifetime Member

Equipment
L305DT, B7100HST, TG1860, TG1860D, L4240
Mar 27, 2014
13,817
5,559
113
40 miles south of Kansas City
Any farmers nearby? If so ask for a "protein tub". It's a plastic tub that holds about 20 gal. of fluid, they get solid protein for their cattle and when it's all licked out they want to get rid of them. I cut the top off to fit under my tractor and there is plenty of volume left. Works great for draining fluids.

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North Idaho Wolfman

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Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
30,194
6,367
113
Sandpoint, ID
Okay... so I didn't have a digital version of the owner's manual, but I did download the service manual for the L-series from kubotabooks at this link:


Oddly enough, it doesn't have the cab version for the 3430. Perhaps they had discontinued it by the time this book was written (the book looks to be from 2003). I need to run out to my tractor and get the S/N to make sure I get the right manual with the right fluid volumes. North Idaho Wolfman--if you have the owners manual I'd really appreciate a copy. Can you send it through a PM, or should I PM you my email address?

As far as oil, oil filter and fuel filters go, I likely change them too often. By that I mean that I change them annually even though I likely don't use my tractor more than 10-20 hours per year at this point. As for the hydraulic oil and filter, I know that I've never changed them, but it could have been done when I used to get the tractor serviced. BUT... the last time it was at the dealer has likely been 10 years, so it's definitely time. I have never even considered it, and I don't know why.

Regarding the clutch, do you mean the physical clutch I press when shifting ranges? It has always seemed to work fine, and it even disengages the PTO when pressed. This may not be what you're talking about, however.

I've always wondered (and mind you--I do not know much about hydraulic systems and it may be about to show) if there's some way to "soup up" the hydraulics on the tractor to alleviate the slow uphill performance. For instance, if I move the FEL when driving up a hill it kills my forward momentum. After all, it's using the same hydraulic system (I assume). Would a higher capacity pump alleviate this? Would a higher capacity pump also alleviate the tendency for my tractor to struggle up hills in higher gears? I've always wondered what would happen if I got a hydraulic pump off of a large excavator and bolted it to my Kubota... LOL!!! It's pretty sad... I'm a Civil Engineer by trade, and I design "hydraulic" systems every day but with water. I'm sure there are similarities, but I've just never delved into true hydraulic systems.

It's good to hear that others have similar issues, but at the same time some users seem to have no problems at all (MountainMeadows--I'm looking/glaring at you). Of course, it's completely different tractor model and that's likely the reason for the disparity.

I think a good start is doing a proper maintenance on the hydraulic system and see if it makes a difference. I definitely don't mind lowering my expectations a bit using a HST on hills--I just want to do all that I can to make it as good as it can be.
You don't need a bigger hydraulic pump!
You just need it to be able to get fluid to work properly!

PM me your serial number of the tractor and I'll tell you or give you the right manuals if I have them!

DO NOT go by the volumes listed in the manual they are never right, go by the sight glass or dipstick, only use the volumes as a ball park for how much fluid to have on hand!

The hydraulic pump and the HST pump and semi connected but they are separate systems.
But you need the complete hydraulic system to work properly for the HST system to work properly.

Things that can effect both hydraulic systems adversely are plugged filters, bad fluid, bad or maladjusted relief valves, suction line leaks causing them to entrain air into the systems, and FUEL system, yes Fuel system issues like dirty plugged filters will pull the whole system performance to the ground and make everything wacky and wonky!

Yes the mechanical clutch need to be checked and adjusted, yes the one you push to disconnect the PTO and shift ranges, if it's slipping everything else goes out the door!

Fluid Type is SUPER important on HST especially these older HST that where a little pickier!

SUDT2, yes your mouth will drop when you pay the price but there is NO real or good alternative or substite fluid!

Kubota Filters, aftermarket filters are horrible with HST systems!

After you do all the filters and fluids (including the front axle (it's separate that the main hydraulic fluid system) then you might need to get some gages and start checking and playing with the Hydraulic system pressures, because I'll be they are way off.

PHEW, I think I've covered it all.
 

JonathanEngr

New member

Equipment
Kubota 3430 HSTC
Mar 15, 2023
7
0
1
North Carolina, US
Wolfman--thanks!!! I've always used Kubota filters and oil, so I'll do the same with the hydraulic system. When my cylinder seal burst I was afraid to do anything with my tractor without adding some fluid, so I bought the type specified at TSC (I just looked and it says Kubota UDT on the container, but not Super UDT2 like you mentioned) . I'll just keep that around to use in my wood splitter.

I always love buying new toys, and I'm not afraid of trying something new most times. Regarding the gauges, what types of gauges and what would be the cost? Would it be better to just take it to the dealership to get everything checked? I know they used to have a mechanic there that everyone said was simply amazing, but I know he's gone now. If it's something that should be checked annually, etc., maybe it's just worth buying a set instead of loading and hauling my tractor for a 2+ hour round trip every year.

I'll definitely check levels with the dipstick. I assume overfilling hydraulic fluid can be as bad as overfilling oil?

I did see a video on adjusting the "play" in the mechanical clutch as well as brakes. Is this what you're speaking of, or is there another adjustment I need to look into?

D2Cat--that's a huge container! Will it even fit under a tractor? LOL! We have a few farmers around here, but not like you see in the midwest. I'm not sure if we have any commercial farms in the area other than Case Farms chicken houses. I'll see if I can find an oil container larger than 5 gallons to catch all of the fluid, and I'll call the county waste management folks to see where I need to dispose of it. I don't suppose there's a good use for used hydraulic oil??
 

PoTreeBoy

Well-known member
Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
2,805
1,522
113
WestTn/NoMs
You can take the hydraulic oil anywhere used motor oil goes. Some people burn it to heat their shop or for fire starter.
 

The Evil Twin

Well-known member

Equipment
L2501, LA526,
Jul 19, 2022
2,814
2,825
113
Virginia
Did you make sure the brake lock truly released? I've thought mine did when I stepped on the brakes only to realize it did not. Takes a good solid press.
No issues going up a 3% grade in H unloaded with only 600 lbs on the 3 point.
 
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BobInSD

Active member

Equipment
L5740
Jun 23, 2020
361
123
43
South Dakota
Just asking, do lift off the HST peddle while going up the hill? If not, try it. It's almost as if you downshifted a geared machine.

I"ve been moving deep thick snow with my HST the last couple of weeks. If I remember that it's a hydro pedal and not a foot feed it works amazingly well. I haven't had this tractor for that long and this is the first year I've really internalized that. (Less snow previous years and snow is my main pto hp requirement--we don't have hills!)

I have never been able to use the top auger on my IH-80 snowblower until this year. My JD 3020 had lots more HP but reverse was way too tall. South Dakota snow drifts are like ocean waves. I measured after I had moved snow yesterday, I had some 3 foot tall drifts I cut and other places on the same driveway the bare ice (from last week) was showing. I was able to cut through a drift out on the road that was taller than the mouth of the snowblower. Low and slow, let off the pedal enough to keep the PTO above 500 and let 'er eat. I really like my "new" tractor!
 
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