How to change the filter for transmission/hydraulic oil without changing oil?

SmallChange · Nov 27, 2020

Just did my 50 hour first maintenance on a new tractor (New Holland WM25 with manual gearbox). This tractor has a common sump for the transmission oil and the hydraulic fluid, so it's just one fluid. Maintenance schedule calls for the suction filter on the transmission/hydraulic oil to be changed at 50 hours and then at every 250 hours. It also calls for the fluid itself to be changed but only every 500 hours.

So I tried to do this today. I was following the Manual, though at some point I thought, "Suction filter? Huh, I guess it operates at negative pressure or something."

And close to 6 gallons of oil rapidly poured out when I got the filter off. It's the lowest point in the system, and I don't see any shutoff. The manual says nothing about it.

So, two questions:

1) I'm not starting or moving the tractor, and all implements were already resting on the ground and not in float, but it's going to sit maybe 3 days before I can get fluid, so, after I replace all the fluid, will I have to do anything else like bleed the system or prime some pump to fix air in the wrong places?

2) How was I supposed to do this? The 500 hour service intervals will be fine, as I will drain the fluid, change the filter, and replace the filter. But the intervals at 250, 750, 1250 et cetera are called out as filter change only, no fluid change. How am I supposed to do that? The fluid pours out so fast!

Thank you!

P.S. Just to be clear, this is only the transmission/hydraulic oil I'm asking about. Engine oil and filter are a whole separate deal and that went just fine.

3gunr · Nov 27, 2020

If you drain the fluid into a clean container , just pour it back in. Some use a shop vac . putting it over the fill spout with a small nozzle . it creates enough suction to keep the oil from draining. I have not tried this but others on here say it works.

jaydee325 · Nov 27, 2020

SmallChange,

Chalk this up to a lesson learned.

For others, make sure you understand what to expect whenever you open any system on a tractor. If you question the manual, ask some questions before opening the tool box!

When I did the 50 hour service on my tractor, I was ready. Big pan under the filter and new filter in hand ready to screw on as soon as I dropped the old one. I had to add about 2 quarts to bring it back to full. Yes, I'm aware of the shop vac trick but for me it just does not seem worth the effort considering being prepared to "drop and spin" a new filter on and then add 2 quarts to an 8 gallon capacity system.

mrmikey · Nov 28, 2020

If you can use a vacuum on the reservoir it'll prevent the fluid loss. Just make sure it's on suck and not blow, ask me how I know (that sounded almost erotic in a sick sort of way LOL)...........Mike

Captain Dirty · Nov 28, 2020

SmallChange said:
Just did my 50 hour first maintenance on a new tractor (New Holland WM25 with manual gearbox). This tractor has a common sump for the transmission oil and the hydraulic fluid, so it's just one fluid. Maintenance schedule calls for the suction filter on the transmission/hydraulic oil to be changed at 50 hours and then at every 250 hours. It also calls for the fluid itself to be changed but only every 500 hours.

<snip>

How was I supposed to do this? The 500 hour service intervals will be fine, as I will drain the fluid, change the filter, and replace the filter. But the intervals at 250, 750, 1250 et cetera are called out as filter change only, no fluid change. How am I supposed to do that? The fluid pours out so fast!

As one who had your experience, I used the shop vac trick at 400 hours. See link: https://www.tractorbynet.com/forums...2-kubota-l45-hydraulic-fluid-maintenance.html[/HTML][/URL]

SmallChange · Nov 28, 2020

Well, it is indeed a lesson learned!

It did, thinking back, take me quite a while to get the change done. For one thing, I generally don't unwrap new parts until I have the old one off, because sometimes it becomes clear at that point that I need to return the new part. So, I didn't have the new part at hand, I had to get up and open the box and pull it out first. I also had trouble spinning the new one into place. I tried several times, and it would go on a few turns but stop before sealing. I still don't know what was going on there; seems like crossed threads, but it did make several turns easily and stop pretty solidly, so maybe something unseen got in the way. I spun the old one back on to stop the flow and examine the new one. And of course the old gasket kept staying with the tractor and then falling into the pan so I had to fish it out a couple times.

I wondered if a vacuum would help. Now I know it's OK to try one.

SmallChange · Nov 28, 2020

I do still have a question, though -- do I need to do anything special because it's sitting so long without oil? But at this point I'm guessing I just have to replace the oil before moving anything.

SmallChange · Nov 28, 2020

Ah, I got my answer on that, so never mind -- turns out the dealer is open this morning, which is great as I had some logs to move this weekend! And they confirm nothing special to do after refilling. They were a bit surprised, though, how much I managed to lose.

At least I didn't call service people out for a broken transmission because I had a lever in N. So this is hardly my worst goof.

Thanks everybody!

oosik · Nov 28, 2020

At 50 hours I changed every oil/fluid/grease on my tractor. I saved nothing. My big almost "OOPS". The hydraulic system holds 16+ gallons. Thankfully I did a dry run. I could NEVER pull/replace five gallon pails without massive spillage. The only container large enough - my wife's large Tupperware quilt container. A new quilt container cost around $20, as I remember.

Citydude · Nov 28, 2020

Did you get the new filter to seat and seal?

K5lwq · Nov 28, 2020

oosik said:
At 50 hours I changed every oil/fluid/grease on my tractor. I saved nothing. My big almost "OOPS". The hydraulic system holds 16+ gallons. Thankfully I did a dry run. I could NEVER pull/replace five gallon pails without massive spillage. The only container large enough - my wife's large Tupperware quilt container. A new quilt container cost around $20, as I remember.

:laughing: I am sure you wiped it out so she could put her quilt back!

oosik · Nov 28, 2020

Not a chance there - 5Klwq. I bought her a new one. That's how I remember the price. If I would have tried that trick - - bad dreams of my wife pulling a Lorena Bobbit.

WranglerX · Nov 28, 2020

Maybe be prepared in future with big tub.....

Dale

Texasmark · Nov 28, 2020

To each his own. My method is to have a catch container to catch the loss. Have the new filter conveniently near by. Get the filter unstuck and ready to back off easily. Spin it off using both hands, one on either side as fast as you can and stab the new one, reversing the process. Even on 4x10 spin ons, you'd be surprised how little you spill. I think the main thing going into it is knowing what you are up against and not being panicked when more comes out than you thought you'd have.....like what comes out on changing an engine oil filter. When finished, check the level and top off if necessary.

On catch pans, I use Dollar General plastic rectangular tubs, with one end cut down so I can work the filter. Use the same one for engine oil changes...slides easily up under the equipment whereas 5 gallon buckets are not the right choice.

k0ua · Nov 28, 2020

Just so you all know, there is another way beside the vacuum. It is called stop up the vent hole. Find the vent hole for the tractor transmission/reservoir. On Kubota's it is under the seat. Little rubber shepherds crook. For a Kioti it is built into the filler rubber cap. Again a crook pointing down. Stop up that crook's hole. Usually a number 8 sheet metal screw will work fine. BUT DON'T FORGET TO TAKE IT BACK OUT WHEN YOU ARE FINISHED. Don't ask me how I know. Now have filter unwrapped and oriented to grab. Remove old filter and quickly put on new filter. Usual spill is less than 1/2 quart. Why does this work you ask? Because without the vent hole above the liquid line air cannot get into the reservoir. The only way air can get in is for liquid to come out the filter hole. Sure a little liquid comes out, and a little air gets in the same way, BUT it is VERY little. Less than 1/2 a quart if you are ready.

Oh by the way if you forget to remove the vent screw and cycle the loader when the loader comes down the dipstick gets blown out into the yard and you get to go look for it. As you may or may not know every time you cycle the loader or any 3pt implement, a large quantity of air gets sucked into your reservoir and when the loader or implement is lowered a large amount of fluid goes into the reservoir and the same volume of air is blown back out the vent. Yes moist humid air is sucked into your transmission all day. And as long as you run the tractor enough to get the oil hot the water vapor goes back out as vapor and does not condense in the bottom of the cold transmission as water. There now you all learned something (or not) and it was free.

bigtiller · Nov 29, 2020

k0ua said:
Just so you all know, there is another way beside the vacuum. It is called stop up the vent hole. Find the vent hole for the tractor transmission/reservoir. On Kubota's it is under the seat. Little rubber shepherds crook. For a Kioti it is built into the filler rubber cap. Again a crook pointing down. Stop up that crook's hole. Usually a number 8 sheet metal screw will work fine. BUT DON'T FORGET TO TAKE IT BACK OUT WHEN YOU ARE FINISHED. Don't ask me how I know. Now have filter unwrapped and oriented to grab. Remove old filter and quickly put on new filter. Usual spill is less than 1/2 quart. Why does this work you ask? Because without the vent hole above the liquid line air cannot get into the reservoir. The only way air can get in is for liquid to come out the filter hole. Sure a little liquid comes out, and a little air gets in the same way, BUT it is VERY little. Less than 1/2 a quart if you are ready.

Oh by the way if you forget to remove the vent screw and cycle the loader when the loader comes down the dipstick gets blown out into the yard and you get to go look for it. As you may or may not know every time you cycle the loader or any 3pt implement, a large quantity of air gets sucked into your reservoir and when the loader or implement is lowered a large amount of fluid goes into the reservoir and the same volume of air is blown back out the vent. Yes moist humid air is sucked into your transmission all day. And as long as you run the tractor enough to get the oil hot the water vapor goes back out as vapor and does not condense in the bottom of the cold transmission as water. There now you all learned something (or not) and it was free.

That's why we come here.....good explanation, keep em coming. :thumbsup:

SmallChange · Dec 2, 2020

Thank you, everybody!

As to the crook on the top of the Kubota hydraulic space... so THAT'S what that thing was! (but that was my old tractor not the current one).

Yes, I did get the new filter to seat. I don't know what kept going wrong the first several times. I was getting a pretty good stream draining out, like the gap must have been at least 1/16" and maybe 1/8". It would rotate several turns and then stiffen considerably, which felt like it was seating, but visually it obviously wasn't. The old filter gasket kept sticking to the tractor rather than coming off with the filter, but I knew that and was dealing with that. I felt for some other obstruction but never found it. Of course I was frantically trying to stem the tide, so it wasn't a great time for thoughtful examination and testing ideas. I'm stuck clueless as to what the problem was. However, eventually it worked, and worked perfectly well as I'd expect with no question about it, and I wasn't about to experiment any further.

About the vacuum cleaner idea, I wonder if the vapor over the oil could be combustible, ignited by the brushes in the vacuum cleaner motor. But I think if it was, that's what most of the stories would be about.

So now I have a NEW PROBLEM. The loader hydraulics are very spongy. I often park with the loader close to the barn door, and just walk across the blade edge if I want to take the shortcut in my fairly small storage area. And I generally get the bucket pretty level when I park and shut down. But yesterday I noticed the bucket was curled a bit and still resting on the ground, and when I walked across it, the loader arms and the bucket were both flexing significantly under my weight. Tractor's new, with nice tight joints, but I could feel with my finger that my body weight was moving the cylinder rods in and out a good quarter inch. Now, I could stand to lose a few, and keep some of my ballast right behind the steering wheel, but this is definitely off!

What I had done after my refill, without having let anything hydraulic move, was to run for a while until the engine was warm. I wanted the air in the filter and lines to get pumped into the tank, not into any cylinders. Only then did I cycle the loader arms, the bucket, and the 3 pt. But I think I must have air in there all the same. I did also notice an unfamiliar, faint, high pitched whine when I started, before I used any hydraulic motions. So I've been reading up on getting rid of air. Any advice would be VERY APPRECIATED!

LouNY · Dec 2, 2020

Most systems will self purge the air out,
just fully stroke all the cylinders several times.

SmallChange · Dec 2, 2020

LouNY said:
Most systems will self purge the air out,
just fully stroke all the cylinders several times.

Thanks! I'm going to try this at lunchtime. I have a urethane edge for the bucket to install, anyway!

And I'm not above being amused by watching things go up and down again and again....