NX6010 hydro transmission issues

[kapper]

Well, as some of you know I've been complaining about my hydro transmission seemingly 'slipping,' or having an excessive lag time. The Dealer, who has been fantastic so far, came to pick it up last week and they recalibrated the hydro. They tested it for about 2 hours and it worked great. They brought it back and I went to work on the new driveway project and it worked great!.... For about the first 3 hours...

Then, it started slipping, or hesitating again. So, yesterday Little Tractor sent out Mike, who I believe is the head mechanic. He again recalibrated the hydro and this was him test driving it. He was nice enough to level some dirt that I had drying out! Anyway, it was a good visit because between the two of us going over the issue, it caused him to identify two potential problems!

The first was that (If I have this all correct) on the newer tractors Kioti was putting on some hydro filters that the screens were actually too fine. They have swapped out a few filters (that were the next level down on screen size), to increase the hydraulic flow. He told me the technical specs/numbers on the filters, but I don't recall that part, but you get the idea.

Secondly, he saw that I have the 3rd function on the front and he looked at the valve used on it, and said it was a 'small' valve and that it was likely only allowing 8 gpm, when the system is pumping 12gpm (the part not including the power steering, as the whole system is like 17 gpm). He had this exact same issue on a DK shuttle tractor when a 3rd function was installed with a valve that was too small. The shuttle was also kind of 'slipping,' would not move very well, and was just plain tough even getting it to shift smoothly.

So, he ordered two new hydraulic filters and is going to get a bigger valve for the 3rd function. I am very pleased with that! I was really worried that this was going to be one of those 'phantom' issues that would net get resolved! I was beginning to wonder if they really believed me when I described what was happening!! Because, of course when they tested it, there was no problems!

The main symptom we identified was that each of the time it started acting up I had been doing loader work for a couple hours. So, it was HEAT that was consistent. After it got good and hot, then it started acting up, which makes perfect sense that either the filters are a bit too restrictive, and/or that valve, which was causing the fluids to run too hot, and either restricting flow, or possibly (but less likely) causing the solenoids to act up if they were getting too hot.

Hopefully, these changes will cure this thing once and for all!! I'll report back probably next week after they get the changes made. Rock on boys!!

 

[Threepoint]

[snip]I was really worried that this was going to be one of those 'phantom' issues that would net get resolved! I was beginning to wonder if they really believed me when I described what was happening!! Because, of course when they tested it, there was no problems![snip]

When I was little, back before vehicle manufacturers went to unibody construction, I remember one of our cars having a rattle and squeak somewhere down under the dash towards the firewall. It never happened when the mechanic was test driving or riding with us. :laughing:

Kap, thanks for posting your experience. Interesting about the hydro filters on some of the NXs. Got my NX in Spring 2014, so I'll watch for that. But around 70 hrs on her and so far so good.

 

[southerniltractor]

I chose Little Tractor which is 130 miles from my house over another closer dealer just for the reason you describe. They have a great reputation for service after the sale. Regarding the sale, James, Mike and his crew were outstanding to work with. I've had a couple issues with the tractor they were able to walk me through on the phone. The one "major" issue was the 4wd solenoid being inoperative. I brought the tractor back for the warranty work and it has been working fine ever since.

 

[countrybumpkin]

Mines not a hydro unit but I used a DO5 valve for my third function due to a DO3 rating. By the time you add a few fittings and 90 degree adapters and such it can really start to add restrictions to the over all flow through the valve. With my kubota there is many times I may run at full throttle for 2-3 hours with out stopping when bush hogging. With the NX I will now be doing that type of work more often, the price difference at time of buying the valve wasn't a bunch.

 

[IslandTractor]

I am no hydraulic mechanic/engineer, but it seems to me that if the screen was too small that the "slippage" would occur almost immediately. As the hydraulic fluid warmed up it would get through the small screen more easily not have more viscosity. Also, the diverter valve issue seems a red herring too. You don't even use the diverter valve which is in the FEL circuit when the HST is working to move the tractor so why should that have any role at all?

 

[countrybumpkin]

I think what he is getting at with the valve is it's causing restriction and adding to the heat build up of the oil.

 

[MinnesotaEric]

Well, as some of you know I've been complaining about my hydro transmission seemingly 'slipping,' or having an excessive lag time. The Dealer, who has been fantastic so far, came to pick it up last week and they recalibrated the hydro. They tested it for about 2 hours and it worked great. They brought it back and I went to work on the new driveway project and it worked great!.... For about the first 3 hours...

Then, it started slipping, or hesitating again. So, yesterday Little Tractor sent out Mike, who I believe is the head mechanic. He again recalibrated the hydro and this was him test driving it. He was nice enough to level some dirt that I had drying out! Anyway, it was a good visit because between the two of us going over the issue, it caused him to identify two potential problems!

The first was that (If I have this all correct) on the newer tractors Kioti was putting on some hydro filters that the screens were actually too fine. They have swapped out a few filters (that were the next level down on screen size), to increase the hydraulic flow. He told me the technical specs/numbers on the filters, but I don't recall that part, but you get the idea.

Secondly, he saw that I have the 3rd function on the front and he looked at the valve used on it, and said it was a 'small' valve and that it was likely only allowing 8 gpm, when the system is pumping 12gpm (the part not including the power steering, as the whole system is like 17 gpm). He had this exact same issue on a DK shuttle tractor when a 3rd function was installed with a valve that was too small. The shuttle was also kind of 'slipping,' would not move very well, and was just plain tough even getting it to shift smoothly.

So, he ordered two new hydraulic filters and is going to get a bigger valve for the 3rd function. I am very pleased with that! I was really worried that this was going to be one of those 'phantom' issues that would net get resolved! I was beginning to wonder if they really believed me when I described what was happening!! Because, of course when they tested it, there was no problems!

The main symptom we identified was that each of the time it started acting up I had been doing loader work for a couple hours. So, it was HEAT that was consistent. After it got good and hot, then it started acting up, which makes perfect sense that either the filters are a bit too restrictive, and/or that valve, which was causing the fluids to run too hot, and either restricting flow, or possibly (but less likely) causing the solenoids to act up if they were getting too hot.

Hopefully, these changes will cure this thing once and for all!! I'll report back probably next week after they get the changes made. Rock on boys!!

Is your third function a diverter valve or a true third function with two buttons on the joy stick and no need to move the joystick while holding a button to make a third function work?

According to the shop manual, our tractors flow 9.9 gallons per minute to the working hydros so a D03 set-up is fine. With 12 gallons per minute (which is not our tractor's spec but what you get if you back out the power steering from total flow but forget both pump halves each flow 9.9 gallons with one side feeding the HST and power steering and the other side feeding the working hydraulics), we're right on the cusp go needing a D05 setup. I use a D03 with a Eaton electric/hydraulic valve which was the highest quality valve I could find. Because the loader hard lines are all 3/8" anyway, the 7/16" from a D05 set up couldn't be used--athough it would be ever-so-slightly faster than my D03 set-up on our NXs.

I haven't heard of the filter problem. With my 50 hour service knocked out last fall, I'm on my second filter for everything.

 

[countrybumpkin]

Using the DO5 had nothing to do with the flow amount to the front disconnects for the grappler or other things. It is do to the flow going through the valve all the time leading to the rear remotes and three point system.

 

[kapper]

I think what he is getting at with the valve is it's causing restriction and adding to the heat build up of the oil.

yes, this is what the mechanic believes. He had the exact issue before. I guess the valve that came was an 8 gal valve and he is going to get a 12 gal valve.

 

[kapper]

Is your third function a diverter valve or a true third function with two buttons on the joy stick and no need to move the joystick while holding a button to make a third function work?

According to the shop manual, our tractors flow 9.9 gallons per minute to the working hydros so a D03 set-up is fine. With 12 gallons per minute (which is not our tractor's spec but what you get if you back out the power steering from total flow but forget both pump halves each flow 9.9 gallons with one side feeding the HST and power steering and the other side feeding the working hydraulics), we're right on the cusp go needing a D05 setup. I use a D03 with a Eaton electric/hydraulic valve which was the highest quality valve I could find. Because the loader hard lines are all 3/8" anyway, the 7/16" from a D05 set up couldn't be used--athough it would be ever-so-slightly faster than my D03 set-up on our NXs.

I haven't heard of the filter problem. With my 50 hour service knocked out last fall, I'm on my second filter for everything.

I believe it is a true 3rd function. It has two buttons on joystick that function any time u push them.

 

[k0ua]

I wonder if the NX series, has it's charge pump for the hydrostatic transmission from the steering section flow. This is the way DK series works. There is no charge pump in the transmission, the charge pump function gets its fluid after the steering valve gets done with it then on to the oil cooler by the radiator, the hydrostat filter then into the hydrostat transmission. I am not sure where they tapped in for the DO3 valve for the 3rd function, but I would think it would be after the loaders PB connection and heading to the other selective control valves. This is fed from the larger section of the main hydraulic pump. Not the steering section. I am also having trouble understanding this. Other than the heat buildup. Of course the NX may not be the same as the DK either.

 

[MinnesotaEric]

Using the DO5 had nothing to do with the flow amount to the front disconnects for the grappler or other things. It is do to the flow going through the valve all the time leading to the rear remotes and three point system.

At first I thought I needed D05 too until I found the split pump spec in the service manual rating at 9.9 gpm making D05 unnecessary. Using D03 allowed me to mount on top of the transmission for maximum protection instead off offset closer to one of the rear wheels.

Anyway, a D03 open center with P open to T isn't restricting flow at 9.9 gpm. Even through the three valve stack in back, it is only adding 10 degrees.

Joe: You have a true 3rd function. Why they used a small valve is baffling because the entire output of the pump goes through the valve in an open center system.

For those who do not know, an open center hydro system is like a spray pump where the water goes round and round until it is needed, at which time it is diverted off in another direction by a valve. A closed center system is like the water system in your house: always under pressure and fluid doesn't move until a valve is opened. So at wide open throttle, Joe's tractor wouldn't be getting all the flow available. However, due to the other side of the pump servicing the HST and power steering, too small a valve body would't effect flow to the HST and power steering.

 

[countrybumpkin]

Do you know what valve they had at first, I can't believe they would have used something smaller then a DO3 the first time.

I couldn't get a good straight answer on the gpm I was getting 10 - 12 so I chose to go ahead and use the DO5. I had plenty of room to mount it up on the side of the trans out of the way. I did make a plate to cover the access opening to keep mud or debris out.

 

[MinnesotaEric]

Do you know what valve they had at first, I can't believe they would have used something smaller then a DO3 the first time.

I couldn't get a good straight answer on the gpm I was getting 10 - 12 so I chose to go ahead and use the DO5. I had plenty of room to mount it up on the side of the trans out of the way. I did make a plate to cover the access opening to keep mud or debris out.

I'm wondering if they didn't use a sub plate and instead used a double valve body with a pair of solenoids. Something like this: SAE 8 6 GPM DOUBLE SELECTOR VALVE 12 VDC P15544-2

We won't know unless Joe takes photos.

 

[countrybumpkin]

Yeah, I'm sort of curios now.

 

[kapper]

I'm wondering if they didn't use a sub plate and instead used a double valve body with a pair of solenoids. Something like this: SAE 8 6 GPM DOUBLE SELECTOR VALVE 12 VDC P15544-2

We won't know unless Joe takes photos.

OK, here's a picture. I spoke with the owner today. He said it is a 12 gpm valve, and they have ordered a 20 gpm valve. We did not get into the details, but presumably the whole 17 gpm is flowing through the entire system? Or does it have something to do with the location of the 3rd function valve? It is located on the passenger side just under the step to get up into the cab. I sure hope this works.... All I know is that when I start it and it is cold and I hit the pedals, they respond instantly. Then when it warms up it starts slipping, or having the delayed reaction. I also noticed the power steering is acting strange too.... Does this make sense??

 

[kapper]

OH, and he also said that when they get the new valve, that they have to re-work the hydraulic connectors and change them all up for some reason..... It won't be just simply swapping out the 12 gpm for the 20 gpm...

 

[countrybumpkin]

Well that's a DO3 valve , and sounds as if they are replacing it with a DO5. I'd really be curios as the the oil temp at the point in which it starts acting up. The valve should be plumbed between the loader valve and the inlet on the rear remote block. Eric said his Manual said 9.9 gallon flow on that part of the system. When I was asking my dealer and a few other sources I was getting answers from 10 - 12 gpm never could get a defiant answer so I went ahead and went with the DO5 just to be on the safe side. Mine is a gear shuttle so I have no clue on the hydro drive system as to where or how much flow is used for that part.

 

[countrybumpkin]

Only thing I can think they are doing that for is to match the valve flow with the new quick connects , looks like they have 3/8 on it know and will more than likely go to 1/2. I really don't see a need to do that but it's there decision. Only time that is going to have flow is when opening or closing the third function and unless your just opening and closing your third function 3 or 4 times a minute or more for hours straight, I can't see that adding much to the oil as for heating it up the valve itself has the oil flowing through it at all times so if it is restricting it for some reason that would build heat after a bit.

Do keep us up to date.

 

[MinnesotaEric]

OH, and he also said that when they get the new valve, that they have to re-work the hydraulic connectors and change them all up for some reason..... It won't be just simply swapping out the 12 gpm for the 20 gpm...

You have a sub plate that looks like it is a D03 size. Their mounting plate is pretty clever for getting it in there. Your entire system is sitting where I mounted a hydraulic "wiring loom" to guard the hydraulic lines and prevent them from getting into the HST pedal linkage.

My 3rd function requires three custom made plates, and four custom-length hoses just to plumb to the quick disconnects (not to mention the electrical harness that uses weatherpac electrical connectors) and is an order of magnitude higher in cost as a result.