Changing Super UDT2

[DustyRusty]

As we all know, the hydraulic system is a closed system and the oil in the system is not being contaminated like engine oil is. Many years ago when visiting the Bobcat dealer with a friend who was bringing his Bobcat in for service, he asked the service manager when it was time to change the hydraulic oil. The response was that they don't change the hydraulic oil based on low hours, but only when the machine gets 900-1000 hours on it or it has gone 3 or 4 years. This begs the question, why does Kubota want the hydraulic oil changed at 200 hours and only the filter changed at 100 hours?

 

[TheOldHokie]

As we all know, the hydraulic system is a closed system and the oil in the system is not being contaminated like engine oil is. Many years ago when visiting the Bobcat dealer with a friend who was bringing his Bobcat in for service, he asked the service manager when it was time to change the hydraulic oil. The response was that they don't change the hydraulic oil based on low hours, but only when the machine gets 900-1000 hours on it or it has gone 3 or 4 years. This begs the question, why does Kubota want the hydraulic oil changed at 200 hours and only the filter changed at 100 hours?

To start your basic premise highlighted above is incorrect. The hydraulic oil is constantly picking up contaminants during operation. Thats why the system has multiple filters.

Speculation as to the recommended schedule ? The 100 (50?) hour filter change is probably intended to account for the presence of any detritus left from the manufacturing process and higher than normal wear byproducts generated as the moving parts bed down.

Dan

 

[GreensvilleJay]

Well the cynic in me says it's a 'make money' reason, plain and simple.

After all there are millions of HST units in North America alone that NEVER get their oil changed or their filters cleaned.

I've owned dozens of riding lawn mowers, garden tractors and the ONLY ones I COULD change a filter on were the early 70s Fords. I'm still cutting grass with an early '90s Cub Cadet.
From a hydraulics viewpoint, no different. You have a tank,pump,motor, oil. Extras like valves and cylinders make no real difference.

 

[mikester]

To start your basic premise highlighted above is incorrect. The hydraulic oil is constantly picking up contaminants during operation. Thats why the system has multiple filters.

Speculation as to the recommended schedule ? The 100 (50?) hour filter change is probably intended to account for the presence of any detritus left from the manufacturing process and higher than normal wear byproducts generated as the moving parts bed down.

Dan

Just to add - your hydraulic tank is vented to the atmosphere - it isn't a closed system by a long shot.

Remember - Heat causes the oil to degrade.

I think geared tractors will see less heat in the hydraulic oil unless you are running demanding attachments with hydraulic pumps/motors.

I've noticed my M59 HST works noticeably better after a 200h oil change - this machine runs way hotter than my similar horsepower TC55DA with EHSS. M59 has bigger pumps and moves a lot more oil around. For me oil and filter maintenance is cheaper than replacing pumps and buying new machinery.

At the end of the day you can save a lot of money by skipping oil and filter changes. Stick it to the man.

 

[D2Cat]

On Grasshopper mowers they list the hyd oil changed at 1000 hrs. I asked the tech/dealer how they came to that number. He said at one time they had nothing published for change of hyd oil. They got so many folks asking when/ why etc. the engineers said 1000 just to satisfy the folks. Engineering also said they'd prefer 1500 hours because the greatest chances of problems is when the system is opened. If it's not leaking leave it alone was his final comment.

 

[TheOldHokie]

On Grasshopper mowers they list the hyd oil changed at 1000 hrs. I asked the tech/dealer how they came to that number. He said at one time they had nothing published for change of hyd oil. They got so many folks asking when/ why etc. the engineers said 1000 just to satisfy the folks. Engineering also said they'd prefer 1500 hours because the greatest chances of problems is when the system is opened. If it's not leaking leave it alone was his final comment.

You are compariimg apples and oranges.

Zero turns fall into two basic categories. Lower end models typically use a sealed belt driven hydrostatic transaxle. Higher end models (e.g the Gtasshopper G2 and G3) use a standalone belt driven hydraulic pump and individual wheel motors.

Zero turns also dont have wet brakes and PTO clutches that shear the oil and load it up with wear particles.

A Kubota HST tractor is an entirely different concept. The HST pump shares a common sump with the brakes, clutches, and auxilliary hydraulics. It is directly coupled to a hydraulic motor that shares that same sump as the implement and power steering pumps and powers the wheels via a driveshaft, differential, axles, and reduction gears. All of those things generate wear particles and contribute to oil breakdown and oxidation far in excess of anything in a ZTR.

The oil used in a Kubota HST has to do many things and it sees far more contamination than any zero turn. A Kubota HST is also far more work and expensive to repair when/if it does fail.

Personally I will change the oil and filters in my Kubota HST(s) at factory recommended intervals. If you do a little research I think you will find the other compact tractor OEMs have very similar schedules.

You are certainly free to adopt the schedule and fluid recommendations promulgated by Grasshopper, Skag, Gravely, Bad Boy, Cub Cadet or any of the other ZTR or lawn tractor companies but dont fool yourself into thinking they are comparable systems.

Dan

 

[ItBmine]

And how many people are careful enough (I am) to perfectly clean their couples before they plug in their remotes. There's another path for contaminants.
I'm on the side of changing all my fluids often. Oil is cheaper than parts or machine replacement.

 

[ItBmine]

Also another reason I don't subscribe to the "buy bigger" theory. I buy machines sized to their purpose, so now as in the case of my most used tractor (the B2620 that does all the mowing) I'm not changing huge volumes of oil when I service.

 

[D2Cat]

You are compariimg apples and oranges.

Zero turns fall into two basic categories. Lower end models typically use a sealed belt driven hydrostatic transaxle. Higher end models (e.g the Gtasshopper G2 and G3) use a standalone belt driven hydraulic pump and individual wheel motors.

Zero turns also dont have wet brakes and PTO clutches that shear the oil and load it up with wear particles.

A Kubota HST tractor is an entirely different concept. The HST pump shares a common sump with the brakes, clutches, and auxilliary hydraulics. It is directly coupled to a hydraulic motor that shares that same sump as the implement and power steering pumps and powers the wheels via a driveshaft, differential, axles, and reduction gears. All of those things generate wear particles and contribute to oil breakdown and oxidation far in excess of anything in a ZTR.

The oil used in a Kubota HST has to do many things and it sees far more contamination than any zero turn. A Kubota HST is also far more work and expensive to repair when/if it does fail.

Personally I will change the oil and filters in my Kubota HST(s) at factory recommended intervals. If you do a little research I think you will find the other compact tractor OEMs have very similar schedules.

You are certainly free to adopt the schedule and fluid recommendations promulgated by Grasshopper, Skag, Gravely, Bad Boy, Cub Cadet or any of the other ZTR or lawn tractor companies but dont fool yourself into thinking they are comparable systems.

Dan

Dan, didn't intend to get you on a "high horse". I am not comparing anything to anything else, I just made a post about a particular brand and their recommendations.

 

[mcmxi]

I buy machines sized to their purpose

As do many, but some have bigger purposes.

 

[ItBmine]

As do many, but some have bigger purposes.

Obviously, but I still laugh at all the suggestions for moving from a BX or B to an M to mow a 2 acre lawn, LOL
And I do have larger tractors, I just don't use them to do all the jobs my B will do.

 

[number two]

I have read more than once that the manufactures are being pressured to specify less fluid replacement intervals to conserve resources.
Green movement I guess.
Good Luck!

 

[whitetiger]

Zero turns also dont have wet brakes and PTO clutches that shear the oil and load it up with wear particles.

Begining with the ZD300 series, they use wet brakes and all ZD series have had a wet clutch.

 

[TheOldHokie]

Begining with the ZD300 series, they use wet brakes and all ZD series have had a wet clutch.

They are the very high end exceptions and not the rule.

And to my actual point - they also have an external spin-on hydraulic oil filter and the oil and filter change interval is 400 hours.

Dsn

 

[mcmxi]

Obviously, but I still laugh at all the suggestions for moving from a BX or B to an M to mow a 2 acre lawn, LOL

Yeah, that is funny. My tractor journey is BX > MX > M which has worked well for me, but I agree, the right tool for the job is optimal, but it can be prohibitively expensive to accomplish that so most of us compromise in some way.

 

[ItBmine]

Yeah, that is funny. My tractor journey is BX > MX > M which has worked well for me, but I agree, the right tool for the job is optimal, but it can be prohibitively expensive to accomplish that so most of us compromise in some way.

Do you mow your finished lawn alongside you house with your M? LOL

Those are the only posts I am bashing here.....when the OP says right up front they have a small yard and need to mow their lawn. Then everyone has them talked up from a BX to a Grand L 6060 cab, LOl

 

[fried1765]

Do you mow your finished lawn alongside you house with your M? LOL

Those are the only posts I am bashing here.....when the OP says right up front they have a small yard and need to mow their lawn. Then everyone has them talked up from a BX to a Grand L 6060 cab, LOl

Zero turn mowers are MADE for mowing lawns!

 

[mcmxi]

Do you mow your finished lawn alongside you house with your M? LOL

Those are the only posts I am bashing here.....when the OP says right up front they have a small yard and need to mow their lawn. Then everyone has them talked up from a BX to a Grand L 6060 cab, LOl

For the record, I'm not disagreeing with you. I just think it's funny that your example is basically the journey I took. As for mowing, I use a Honda walk behind around the house since the area is small, and sometimes use the MX and flail for the heck of it. Mostly I cut larger parcels in the 10 to 20 acre range.

Had I kept the BX25 I really don't know what I'd use it for other than perhaps the backhoe for digging some holes.

 

[lugbolt]

They are the very high end exceptions and not the rule.

And to my actual point - they also have an external spin-on hydraulic oil filter and the oil and filter change interval is 400 hours.

Dsn

yup and most of them have a suction screen inside too that rarely if ever gets cleaned.

a lot of the zero turns (outside the ZD and ZG300 series) have spin on filters as well. They gotta keep everyone on their toes I guess

and for the sake of argument the last time I changed the fluid in my zg127s, I didn't have any oil that it calls for so I dumped some super UDT2 into each side. It's a little quieter and responds faster to changes in speed and direction, however the expansion rate is a lot higher-the expansion tank barely reveals any fluid when cold, after mowing my acre & a half, it's almost coming out of the tank. the old 5w50 might have been 1/4 full at that point. It's not running any hotter (verified with IR) but it sure wants to puke.

 

[ItBmine]

For the record, I'm not disagreeing with you. I just think it's funny that your example is basically the journey I took. As for mowing, I use a Honda walk behind around the house since the area is small, and sometimes use the MX and flail for the heck of it. Mostly I cut larger parcels in the 10 to 20 acre range.

Had I kept the BX25 I really don't know what I'd use it for other than perhaps the backhoe for digging some holes.

I understand. I just like to try and not discourage newbies when they are trying to afford their first tractor. I like to promote what the little affordable ones can do. They really are workhorses. We all had to start somewhere.
And as a plus, used Kubota's get you the same price you paid for them new now, so no big deal trading up.