NX6010 HST stops moving

[joro2548]

Have a NX6010 HST and for the past two years, it will periodically cut out of forward motion ( like a tranny that would slip into neutral on a car ), while the engine rpm stays at full throttle. Won't go forward or backward. When I take my foot of the petal and let the rpm's go down to idle and wait 10 to 15 seconds, then re engage the forward petal. it will go again. Generally happens under load, like going up a hill or blowing snow, but occasionally on the level with no load. Will only happen at high rpm. This is an intermittent problem that the dealer has tried to fix but to no success. Of course it NEVER happens at the dealer when they try to make it happen. Any ideas?

Frustrated in Minnesota

 

[Wagtail]

When you say "full throttle" do you mean just that or Max revs for the task at hand?

My 4105 has a 'sweet spot' at just a titch over 2000, then there's the working with the PTO running revs and the 'on the road' revs (2500). Full/maximum revs would only be used in a dire situation and not for long as it may over-tax an HST.

 

[Threepoint]

Joro2548, I'll mention this just to rule it out as the cause. Are you certain that you aren't inadvertently hitting both the forward and reverse hydro pedals at the same time? Most commonly happens doing loader work with heavy boots on (or very large feet ), but the symptoms are similar to yours.

Simultaneously catching the second pedal with the edge of your foot, even momentarily, will put the fly-by-wire HST control into "safe" mode, and you'll be dead in the water for a few seconds until it resets. If you press either pedal in the interim, before it resets, it will keep cycling in safe mode.

 

[Jchonline]

Can you catch a video of it happening? This would at least provide some additional info to your dealer.

 

[joro2548]

I use the linked in pedal switch so that as I press the forward pedal down, the rpm's increase, like on a car pedal

 

[joro2548]

definitely not hitting both pedals at the same time. Not saying it's never happened, but not consistently when having this problem. Thanks

 

[joro2548]

What does the fly by wire control. Maybe the electronics of the fly by wire are failing intermittently. As I mentioned in the initial post, when the drive kicks out, the rpm's do not drop

 

[Threepoint]

What does the fly by wire control. Maybe the electronics of the fly by wire are failing intermittently. As I mentioned in the initial post, when the drive kicks out, the rpm's do not drop

Joro2548, I don't know the particulars of the HST fly-by-wire circuitry, but the idea that your issue might be electrical seems quite logical. See post #1123 in the following TBN thread from a couple of years back: https://www.tractorbynet.com/forums/kioti-buying-pricing/315694-my-nx6010-113.html

I haven't checked, but I suspect the NX service manual has an explanation of how the HST pedals signal the transmission, along with a circuit diagram. Do you have access to one? IMO, this is certainly worth raising with your dealer's tech. Your sudden loss of forward and reverse operation seems identical to what happens in "safe mode" when inadvertently pressing both pedals. Just speculating here, of course, but it might even be as simple as a loose or damaged wire, or a faulty pedal-pressure sending unit.

Here's a thought that might help with the diagnosis. While driving forward and continuing to keep pressure on the forward pedal, use a short length of wood, long screwdriver, etc. to lightly press the reverse pedal momentarily. Watch the dash to see if the CAL light comes on, and if the condition replicates.

Keep us posted on this. These NX tractors have been sold for about five years now, and have been very reliable.

 

[joro2548]

Thanks Threepoint, I will definitely raise this point with the dealer on Monday. Thanks for everyone's input

 

[jabelding]

Have you checked your tire pressure some people have had the same issue and it turned out the tire was slipping on one of the rims. Usually happens with rim-guard filled tires and low tire pressure.

 

[joro2548]

Yes I did check this the other day as I also read of that possibility, but the wheel wasn't spinning. Thanks for the response

 

[MinnesotaEric]

Have a NX6010 HST and for the past two years, it will periodically cut out of forward motion ( like a tranny that would slip into neutral on a car ), while the engine rpm stays at full throttle. Won't go forward or backward. When I take my foot of the petal and let the rpm's go down to idle and wait 10 to 15 seconds, then re engage the forward petal. it will go again. Generally happens under load, like going up a hill or blowing snow, but occasionally on the level with no load. Will only happen at high rpm. This is an intermittent problem that the dealer has tried to fix but to no success. Of course it NEVER happens at the dealer when they try to make it happen. Any ideas?

Frustrated in Minnesota

I think it is a software problem but only if you have the throttle/speed/whatever-it-is-called switch on. If the switch is on, at max throttle in high gear you can jam on the go pedal and the machine will not move. Move the go pedal slower and off you go.

Also this problem can happen if your hydro oil is cold. I put a warmer T-stat into my NX6010 and it fixed all my drivability problems--from the engine not operating warm enough (as in it would go cold at idle at 35 degrees and colder), to faster warm-up of hydro oil, to a bunch more power (because the engine is now operating at the proper temperature).

If the fault isn't something stupid like I've suggested then pull the electrical connections apart and reconnect them--especially the pedal position sensor and the two pin switch that can get disconnected on the underside left hand portion of the transmission.

 

[joro2548]

Thanks,
They are looking at all connections and we will see what happens.

 

[Overtaxed]

Did you ever get a root cause on this? Just wondering if it might be the same problem I have, air in the hydro line. My tractor doesn't stop moving entirely, but it certainly feels like a "slip" and the tire is spinning on the rim (it's not).

Also, Eric, you happen to have the PN for the warmer tstat? I have similar problems, my NX takes a really long time to warm up, and if I let it idle in the cold, it'll get below the middle of the range.

 

[joro2548]

Kioti decided to replace the entire hst system. They have to split the tractor in half to do it. Of course I知 without a tractor until they get the parts and then install them. Hopefully it won稚 snow much intil it痴 finished.

 

[Overtaxed]

Kioti decided to replace the entire hst system. They have to split the tractor in half to do it. Of course I知 without a tractor until they get the parts and then install them. Hopefully it won稚 snow much intil it痴 finished.

Wow, that's extreme.. They're replacing the tranny too, not just the HST "power side" (pumps/filter/etc)? I'd love to know why they are doing that, it seems that the problem is likely on one side or the other, either the pump is a problem or the tranny is the problem, not both, right? In my case, it's obvious the problem is on the power side because all my hydraulics have issues, not just the tranny; my FEL is jerky, 3pt, external hydro accessories. They all "slip", and the reason they slip is because (current theory) the pump is bad and it's putting air in the system. But it's easy to figure out if that's the problem (look for bubbles in the fluid and listen for cavitation).

I'd be happy if they'd do this for me, so, good for you, but man, that's a big repair, just seems there are a lot of things to try before dropping the HST and replacing the whole thing?

 

[MinnesotaEric]

Did you ever get a root cause on this? Just wondering if it might be the same problem I have, air in the hydro line. My tractor doesn't stop moving entirely, but it certainly feels like a "slip" and the tire is spinning on the rim (it's not).

Also, Eric, you happen to have the PN for the warmer tstat? I have similar problems, my NX takes a really long time to warm up, and if I let it idle in the cold, it'll get below the middle of the range.

The Stant 48808 is a drop in replacement. You'll need to get a factory t-stat gasket or make one out of gasket material. I make them out of 3075.