Bought this machine a little while back, had to tear the hyd system down to replace the pump and clean all the lines out. Runs and operates good for the most part. Issue I’m having in when it’s cold it drives good but when it gets hot it starts to not want to pull correctly. I’ll push the joystick forward and it doesn’t move them let off and goes for a second. It’s usable but not enjoyable. It gets much worse when the high flow is on, because I’ll try and barely go forward and it lunges then slows, lunges then slows. It’s like the solenoids go wide open then back off or the high flow is back feeding?. I tried to calibrate it but it fails every time, no codes or errors, just says fwd calibration fail. I’ve checked the drive solenoids and all are within spec. Anything else to check or is this machine going to need a drive pump as well?
Machine serial number please. At what point does it fail the calibration? Oil level correct? Does it act the same with the controls set to "H" pattern? Attach a picture of the top of your hydrostatic pumps.
Yes oil level is correct. It turns the tracks for a minute or 2 then fails. They speed up, slow down, one side turns then the other turns like it’s going through the procedure and after a little bit it fails. I’ll have to try to swapping controls over to H.
Please post the serial number. You scrolled through the monitor and there are no active or stored codes? When the drive starts to act up, does the loader hydraulics still work well? When performing a calibration, the monitor is directing you on what to do. At which point specifically does the calibration say fail. After performing the "Calibrating FWD and REV Thresholds"? Calibrating FWD MAX Speed? Do you have gauges to check the charge pressure?
Serial is 1T0333DMVBD205383 No active or stored codes Loader controls operate smoothly wether hot or cold I go into calibrate hydrostatic, it then says hold fnr to max fwd and I do, then says calibrating fwd threshold, tracks turn for a little bit then it says failed I can buy a gauge if needed
Temperatures shouldn't matter with this, but check the wires that go into the pump solenoid connectors. Give them a good tug to see if any wires are broken. If they are broken, it will be real close to or at the connector. You will either pull the wire out, or you will see the insulation stretch if broke.
Okay I’ll double check that
Wires are all good, after swapping to H pattern I can tell it’s the right side that doesn’t pull when it gets hot. I think the sporadic jumping is from the left side trying to take the grunt of the work to make it move. Also I put it on a fairly steep hill and it wouldn’t pull itself up. Ended up having to back up and go around to get it back to the house. Guess that means I need a new tandem pump? Is it simple enough to rebuild it myself? I’ve rebuilt the drive motors in a bobcat which was easy since it was just replacing o rings
No. Not likely. Being heat related, it might still be one of your solenoids. You could try swapping the right forward solenoid with the right reverse solenoid. Y16 below is for the right side forward along with the one opposite it you can't see for reverse. Did you measure the resistance of that solenoid when the issue was happening? If swapping the solenoids does not change anything, then charge pressure and multifunction relief pressures need to be checked. Since you do not have gauges and based on your symptoms in the "H" pattern, try below:
Thank you, I’ll give that a try today or tomorrow. I believe when I measured the solenoid resistance it was when the machine was at operating temp. If memory serves me correct the right side both measured 4.1 and the left ones measured 4.5
I swapped the solenoids with no change then swapped the reliefs with no change. Something I noticed when I put it in H pattern is that when the right side stalls then push the handle for the left side the left side won’t move as well like I’m making the main relief open. I can push the left side forward or reverse and the machine will do circles but when I push the right side the machine will barely creep and if it’s under a load/on an incline it’ll stall
A test you can perform without gauges. If you remove the two hoses going to the right side motor from the pump, cap the pump with some steel fitting caps. Operate the right side. Does it want to stall the machine?
I’ll have to buy some caps, do you know the size?
-12 (3/4")
Okay thanks, I’ll order some and follow up
Bought some gauges, hooked up and charge pressure at operating temp was around 650-700. I adjusted the relief all the way out and it got down to 550psi. Left side would drop a little then bounce up the 525psi while in use. Right side would drop down to 300psi while in use. Capped off all 4 lines, charge pressure is now 725psi at high idle. Right side drops to around 600psi when engage and the left side drops to 700psi when engaged. There’s about a 100-150psi difference between the sides when stalling them
If you measured 650-700 psi, you could have left it at that. the spec is 500-0700 psi. I'm not concerned with the 100 psi difference with them capped. The drop to 300 psi on the right tells me there is excessive leakage somewhere. What I would like to know is, with the engine at idle, if you can stall the engine with the right side capped, if so, then your issue is in the drive motor. If you could put a 10,000 psi gauge into the forward outlet port of the pump, that could confirm the pump is good. That would show that the pump (this test at fast idle) can reach the high pressure relief setting (4930-5230 psi).
Well here’s the results, went to the hydraulic shop and got the adaptors to hook a gauge to the drive ports. Right side started off maxing out at 5500psi, by the time the oil temp got to 150°f it seemed to struggle to get 4000psi. Swapped everything to the left forward at 150° as well and it does 5600psi. So I guess that’s settled, I’ll need a new pump? What’s the recommended vendors? Unless it’s worth paying nearly double to John Deere for a new one($7100+ tax) also at idle neither side would stall out the engine. The left side defiantly loaded the engine down and spooled the turbo, the right side was negligible
I would rebuild that one in house, possibly could get away with having the rotating group lapped. Maybe need a new valve plate, worst case new rotating group. Could definitely send out to be rebuilt, Stoens is one shop we have used.
I’m willing to do that, have plenty of mechanical ability as I’ve worked on stuff my whole life. Only thing that makes me leery is tearing down the pump, replacing parts, spending the money and still having to send it out because it’s not right. I have the manual which shows the disassembly and assembly which doesn’t seem bad until you start taking out the servo piston. If you think the issues lies in the rotating group then I’ll tear it down and inspect it and order parts as needed
Yes, rotating group is likely scarred. You have swapped reliefs eliminates that. Can your hydraulic shop lap the brass parts?
I don’t have a hydraulic shop, I’m just a welder/mechanic. Based on the video I watched I think I’d have to have a machine shop or maybe a hydraulic shop perform that part of the repair
Here’s a video as well
The bronze plate has light grooves in it, the mating surface of the rotating assembly seems to have .10-.15mm wear on the outside band. The swash plate and the bronze caps on the pistons seem to have a lot of wear though but maybe they’re how it’s supposed to be? I can’t find a picture of a new one to compare. Piston bores are smooth and pistons have superficial scratches(can’t feel with fingernail)
I’ll upload pictures in the morning, I don’t have enough service to get them to attach
The slipper feet are out of spec, they measure 3.63-3.65 and the manual says minimum is 3.68
Remaining pictures
Can't see enough to tell it will need all new, but for sure will need rebuilt/lapped.
That slipper is beyond lapping, in my opinion.
I ended up finding a low hour pump off a 333g from a burned machine. The center section is different so I swapped mine to it. I was able to calibrate the machine and it’s working great now. Having issues with it overheating though, which was happening before, it’ll run for a while then get up to 220°, leave it running at full throttle and it’ll cool down to 205 pretty quick but as soon as I start working the machine it starts to run up again. Thermostat was replaced about 2 weeks ago, water pump is good and coolant is new. Cleaned the coolers real good but it’s doing it after running the machine an hour or 2
Cooling package clean? Has the fan speed been checked? That would be with the engine at fast idle, the hydraulic oil at 110*F and the fan speed control solenoid disconnected. Measure the fan speed with a photo tach. Spec is 2350-2600 rpm.
Yeah the cooling package is clean, cleaned it again yesterday to be sure. Ran it an hour today and it started to overheat again. Measured it at 1580 rpm’s at WOT. Fan speed solenoid is clean and I cleaned it again during the test but it didn’t seem to make a difference. So I guess I’ll need to measure case drain to know what to replace
Can the fan motor be rebuilt? I see there’s a $200 seal kit. Didn’t know if that would be the issue or that it’s probably a mechanical issue and the whole unit needs replaced
If that is with the solenoid disconnected, then that is why you are overheating. Has the charge pump been flow tested or inspected? I see from your serial you have the reversing fan option? The reversing fan directional control valve is could be stuck/sticking. Check your messages.
Charge pump is brand new, that was the original issue when I bought it and apparently it’s taken out everything else with it before it locked up. You helped my diagnose that when I first got it. I went to a hydraulic shop bought a hose to test the flow from the fan case drain. Manual says 17oz in a minute once it starts flowing, I got 32oz in 15 secs. So now it begs the question can I rebuild it with this kit at370557 or do I just get another motor from John Deere?
Take it apart and check the condition. If the gears or housing are wiped, by a new one. If they are in good shape and the only issue is the pressure plate seals, buy the seal kit. My money says if debris from the pump went through, you will need a new one.
Yeah the housing is scratched up, gears are in good shape. So I don’t suppose I’ll get away with just seals?
Nope.
Okay thanks, I got the motor coming so hopefully get some work done with the machine this coming up week. Thank you very much for all your help
Got the new motor on today, was working great from a few hours, decided to reverse the fan but when it switched back to normal the fan was very slow. Cut the machine off and fired it back up and it went back to full rpm. I may have the reverse solenoid wired backwards, I can’t seem to find in the manual where it shows where they go
Check your messages.
Fan solenoids were hooked up correctly. I started the machine and went to put fuel in it and noticed the fan was hardly spinning. Cut the key off and back on then it goes back to spinning at proper speed, ran the machine for a while and turned the fan reverse on twice and both times it flipped from reverse to forward and went back to full speed. At least it’s usable now
When I first start my machine the fan turns very slow till the machine is up to operating temperature. Then it is variable from that time forward.
When the ambient temperature is below 54*F (12*C), the fan will be commanded off for cranking and for the first seven seconds of run time. Once running, it should always be turning. At what speed for what temperature, that is the $1000 question. I only have the specs for when it should reach full speed.
Ran it most of the day Wednesday and Thursday and it did good. Put about 30hrs on it this week. Had a code for a left drive solenoid on Wednesday but it seems it was just a bad connection because it hasn’t came back on after pulling the plug, blowing it out and reinstalling. Then got a code for low fuel pressure because the tank vent got clogged and it sucked in the tank. Been running the multcher cleaning up my property and cutting trails. Reverse fan seems to be operating as it should now, so now I get to focus on the small issues, mainly the front of the cab not sealing and letting a lot of dirt in. Once I get this yard work done I get to do the same diag on my JD 260 that has the same issue. Left drive doesn’t work properly. Seems like you have to push the arm all the way then it goes full power. Not really much of a slow and medium speed to that side and after you work it awhile it stops pulling all together on that side