Hydro oil change or not at 50 hrs. for DK45SE HST.

[ritcheyvs]

I just did the 400 hr service on my DK45s. I believe the dealer told me he did change the hydro oil at 50 hr but I'm not positive. In any case, there was a lot of goo and fine metal particles stuck on the magnets integral to the two drain plugs and the magnet inside the hydro filter. The old oil was dark compared to new stuff. My gear model tractor does not have (or need) drains at the final drives or a HST filter. It might be a good idea to remove and clean the magnets on the drain plugs even if you don't change the oil (assuming your plugs have magnets). By the way, these magnets make it hard to get the threads started when re-installing the drain plugs; the magnetic pull makes it hard to keep them aligned with the hole. Maybe the HST model is different but I'd be inclined to change the hydro oil.

 

[ksbrdmkr]

I think the key is code "M" which puts you on page 7-15 which says to change if contaminated or after the trans is serviced and at 400 hours because the third paragraph says not to change the oil at 50.

 

[k0ua]

Another interesting fact is that Kubota did call for a 50 hour change but now do not. They call for a change of fluid now at 400 hours. So that is what I did when I had the L3400hst.

 

[bmurphy777]

That was my thoughts exactly. Be sure you have a chain wrench to get that "darn" hydraulic filter by the right rear tire off.. That thing is a real bear. Everything else is pretty easy.. Also please remember the engine oil drain plugs thread into an aluminum pan, so re-tighten with care.. Dont forget the 2 final drive plugs by the rear wheels, they are easy to miss. Be sure to get the 2 front axle drains, on some of them the oil comes out pretty slow. On the large main hydraulic drain plug be ready for a "whoosh" of fluid to come out, and I mean fast! I used a large plastic "tote" container as a catch basin, remember you are dealing with a large amount of fluid here. Good luck with it all.

James K0UA

Thanks James, I appreciate the advice. I may get the dealer to do the first 50 hr service anyway but for the next one I will keep your tips in mind!

On a separate note, this forum is an absolutely invaluable source of information for guys like me - ex city dwellers who really have no clue about the finer points of iron wrangling. :laughing:

 

[murphy1244]

Thanks James, I appreciate the advice. I may get the dealer to do the first 50 hr service anyway but for the next one I will keep your tips in mind!

On a separate note, this forum is an absolutely invaluable source of information for guys like me - ex city dwellers who really have no clue about the finer points of iron wrangling. :laughing:

Your not alone.

 

[rjwerth]

I wasn't going to change the oil when I did my 50 hour at the advise from my dealer, but when I drove a screwdriver though the filter to get the freeking thing off, a large portion of it siphoned out so I ended up making an unplanned trip to TSC for 2 small drums of fluid!

 

[Kryton619]

I am new to owning a tractor but certainly not new to hydraulics being an elevator mechanic. I can understand the need to change hydraulic oil in HST tractors but changing the fluid in geared tractors puzzles me.

Hydraulic elevators are typically used in low rise applications up to approximately 7 floors max. The hydraulic oil is never changed. The only time it gets changed is if a submersible pump motor burns up and contaminates the oil, or if over time the buried cylinder rusts out and develops a hole. At this point the cylinder and piston are replaced along with the oil...this is a $50,000.00 repair.

 

[k0ua]

I am new to owning a tractor but certainly not new to hydraulics being an elevator mechanic. I can understand the need to change hydraulic oil in HST tractors but changing the fluid in geared tractors puzzles me.

Hydraulic elevators are typically used in low rise applications up to approximately 7 floors max. The hydraulic oil is never changed. The only time it gets changed is if a submersible pump motor burns up and contaminates the oil, or if over time the buried cylinder rusts out and develops a hole. At this point the cylinder and piston are replaced along with the oil...this is a $50,000.00 repair.

The hydraulic oils is used for lubrication for the entire transmission, final drive reduction, wet brakes and all hydraulic cylinders. There is always metal particles being "ground off" of all of these moving parts. These small particles are suspended in the fluid, and of course the filters catch a lot of them. Also the tractor is subject to much higher temperatures I believe than your hydraulic cylinder only application example. These temperatures would seem to me to help break down polymer chains and lead to degradation of these oils. I am sure it is true that geared tractors are not as sensitive to clean fluid as the high tolerance parts of a hydrostatic transmission, but I believe they will benefit from clean new oil also. Of course these are just my opinions.

James K0UA

 

[ritcheyvs]

I am new to owning a tractor but certainly not new to hydraulics being an elevator mechanic. I can understand the need to change hydraulic oil in HST tractors but changing the fluid in geared tractors puzzles me...

Aside from possible contamination from connection/disconnecting hydraulic hoses. I think the wet brakes and metal particles (from gears) are the main sources of contamination. Maybe also fine particles from deterioration of the rubber hoses.

 

[Kryton619]

The hydraulic oils is used for lubrication for the entire transmission, final drive reduction, wet brakes and all hydraulic cylinders. There is always metal particles being "ground off" of all of these moving parts. These small particles are suspended in the fluid, and of course the filters catch a lot of them. Also the tractor is subject to much higher temperatures I believe than your hydraulic cylinder only application example. These temperatures would seem to me to help break down polymer chains and lead to degradation of these oils. I am sure it is true that geared tractors are not as sensitive to clean fluid as the high tolerance parts of a hydrostatic transmission, but I believe they will benefit from clean new oil also. Of course these are just my opinions.

James K0UA

I would suggest that oil temperatures in an elevator system would be greater than in our tractors. I have measured oil temperatures on many elevators and they range from room temperature to 90 degrees celcius. A busy elevator in a medical building could run at the upper range of that for 12 hours straight.

Aside from possible contamination from connection/disconnecting hydraulic hoses. I think the wet brakes and metal particles (from gears) are the main sources of contamination. Maybe also fine particles from deterioration of the rubber hoses.

I agree...if there are gears in the system I see the need for hydraulic oil changes but is that the case for non HST tractors?