D39PX-21 Stopped Moving

[alandudley]

Hello everyone. I am looking at a D39PX-21 to purchase. SN 1283. The owner said he was running it and it just stopped moving like you kicked it into neutral. Komatsu told him the drive plate was stripped so he tore it down and found that was not the problem. It is partly put back together, the motor is back in anyway, but I don't think he really knows what caused the issue at this point. He also said he has a new hydraulic pump for it so apparently he believes that could be the issue. Someone also told him it could be the alternator but I am not buying that one yet...lol. I am going to try and go look at it tomorrow. Anyone have any ideas what could be the problem or maybe what to look for when I go to see it?

 

[epirbalex]

Hello everyone. I am looking at a D39PX-21 to purchase. SN 1283. The owner said he was running it and it just stopped moving like you kicked it into neutral. Komatsu told him the drive plate was stripped so he tore it down and found that was not the problem. It is partly put back together, the motor is back in anyway, but I don't think he really knows what caused the issue at this point. He also said he has a new hydraulic pump for it so apparently he believes that could be the issue. Someone also told him it could be the alternator but I am not buying that one yet...lol. I am going to try and go look at it tomorrow. Anyone have any ideas what could be the problem or maybe what to look for when I go to see it?

Alternator ? spose he checked the oil levels , filters , screes etc first . Check linkages , I checked the wire diagram for it and it didn't seem to have any role in controlling the transmission . Couldn't find the transmission either so that might not mean much .

https://en.av-gk.ru/catalog/komatsu/d39px-2r/

 

[Simon C]

Alternator ? spose he checked the oil levels , filters , screes etc first . Check linkages , I checked the wire diagram for it and it didn't seem to have any role in controlling the transmission . Couldn't find the transmission either so that might not mean much .

https://en.av-gk.ru/catalog/komatsu/d39px-2r/

Is there fuel in the tank. What is the exact battery voltage across the posts with a meter. Are battery connections clean. Did a battery cable fall off. Does the engine crank over. When was oil changed last. So many questions to answer to start Diagnosing. Simon

 

[Simon C]

Is there fuel in the tank. What is the exact battery voltage across the posts with a meter. Are battery connections clean. Did a battery cable fall off. Does the engine crank over. When was oil changed last. So many questions to answer to start Diagnosing. Simon

Does it have a fuel solenoid? Is there good fuel flow at pump with fuel line disconnected from pump.?

 

[southernman13]

I’ve heard the -21 were ones to have issues. Been told they could blow a hose and leak all the fluid out before u could know it and tear up the transmission. Seems I’ve seen a lot of the newer -22,23 series that have hyd issues. I really want a 39P-23 I think it they are just badd Azz lol but I’m scared of them and they’re a lot of money. Really think the newer series 39/51’s are just the coolest looking machines on the market. I like the -21’s as well but idk. We have an 06 41P-6 and live it but it’s open cab. Good luck please tell what u find out

 

[alandudley]

Ok well taking a chance on the machine and bought it.
Simon C I don't think it is a fuel problem as it was still running but stopped moving. He said he was headed back to the barn and it just stopped moving like you kicked it out of gear so I think the problem is associated with the hst.
I stopped by the local Komatsu dealer and asked for a history and found some interesting results that maybe eludes to the issue. It appears that he had this exact same problem in 2016 and the problem was due to the hst solenoid had failed. He has put only about 60 hrs on the machine since this issue in 2016. The ticket indicated the alternator was checked at 39 volts and subsequently replaced. It also indicated the hst solenoid was bad so the mechanic swapped it with the third gear solenoid and corrected the issue. I did notice the third gear solenoid is not plugged in now. Since the mechanic swapped the solenoid as opposed to replacing it I am hoping the solenoid is the problem again. The owner did drain the hydraulic tank and it appears to be clean with no signs of metal just looking in it with a flashlight. I did remove the charge filter and the hydraulic filter and did not find any metal or anything to indicate a pump failure. I do have the hydraulic pump he removed so I am going to inspect it more closely but do not expect to find a problem there.
I should have the machine home this week and will start troubleshooting as I would like to find the problem before I put it all back together. Incidentally someone has stolen the oil cooler so I am in search of one so if anybody has one laying around let me know please...lol.
Southernman13 I have researched these machines allot and it seems they are pretty reliable. Seems I do see several of them around with a bad final drive though so that may be a bad sign for me...lol. This is a farm machine for me so I am not trying to make a living with it but also cannot afford a major breakdown either.

 

[southernman13]

Well good luck I may have found the issue. Same here seen a lot w final drives gone bad. I just know it don’t take much anymore to cost a lot in repairs. Seems like we earn money just to fix a piece of equipment. That gets old quick lol. Thanks for the update!!

 

[alandudley]

I know what you mean. It seems that since I started buying equipment a few years ago all I do is work on it...lol.

 

[kevinnguyen]

Does your blade still work

 

[alandudley]

No. The blade had stop working too. I have been studying the hydraulic circuit and it looks like the blade pilot pressure comes from charge pump which is bypassed by the brake parking valve. I found that the fusible link for that circuit was blown so I think that may be the culprit. I hope to have the machine back together this weekend to try it out. I have yet to find the source that took out the fusible link though. I check it to ground and it shows about 12 ohms which would only draw about 2 amps so it doesn't seem to be shorted out now. It has a new alternator now so maybe that was the source of the short...I don't know.

 

[kevinnguyen]

No. The blade had stop working too. I have been studying the hydraulic circuit and it looks like the blade pilot pressure comes from charge pump which is bypassed by the brake parking valve. I found that the fusible link for that circuit was blown so I think that may be the culprit. I hope to have the machine back together this weekend to try it out. I have yet to find the source that took out the fusible link though. I check it to ground and it shows about 12 ohms which would only draw about 2 amps so it doesn't seem to be shorted out now. It has a new alternator now so maybe that was the source of the short...I don't know.

Mine have the same problem
Both joystick don’t work with no movement for the blade or drive
I change gear pump and chArge pump still same issue

 

[epirbalex]

No. The blade had stop working too. I have been studying the hydraulic circuit and it looks like the blade pilot pressure comes from charge pump which is bypassed by the brake parking valve. I found that the fusible link for that circuit was blown so I think that may be the culprit. I hope to have the machine back together this weekend to try it out. I have yet to find the source that took out the fusible link though. I check it to ground and it shows about 12 ohms which would only draw about 2 amps so it doesn't seem to be shorted out now. It has a new alternator now so maybe that was the source of the short...I don't know.

Pretty tough on the guy who pulled the motor

 

[dozer777]

je connais quelqun qui a un 39px 21 a vendre jmoi je ne touche pas ce bulldozer tout les operateur que j/ai travaillez avec mon dit la meme chose hypotheque ta maison??

 

[southernman13]

Yeah what he said lol

 

[alandudley]

Ok I have it running now and it still has the same issue. No hydraulics. Neither the blade nor the trans. I know it has to be the charge circuit but not sure what is the cause. I am leaning towards the charge relief valve but not sure if that is it. I thought it may be the solenoid valve bank but I am getting voltage to the parking brake solenoid and the other valves show to be normally closed. I will be checking pressures this weekend to try and isolate the problem. If anyone has any suggestions of where to look or maybe have heard of this before I could sure use the help. Kevin did you get yours fixed? Sounds like we may have the same problem.

 

[southernman13]

Have u spoke with any of the service managers at TEC. They’ve always been helpful to us in the past

 

[alandudley]

Good morning southernman13. I have spoken with the shop foreman and the service foreman at the local TEC and they were very helpful but I didn't have anything but speculation the last time I spoke with them. I am going by there today and have another conversation since I have a little more info now. I have been studying the hydraulic schematic (which is a little confusing to a non-hydraulic guy...lol) and it appears the charge relief valve could be the culprit as it is about the only thing in the circuit with the left safety lever down and the right one up.

 

[nissleyequip]

Good morning southernman13. I have spoken with the shop foreman and the service foreman at the local TEC and they were very helpful but I didn't have anything but speculation the last time I spoke with them. I am going by there today and have another conversation since I have a little more info now. I have been studying the hydraulic schematic (which is a little confusing to a non-hydraulic guy...lol) and it appears the charge relief valve could be the culprit as it is about the only thing in the circuit with the left safety lever down and the right one up.

I have one doing the same thing. What did you find?