Komatsu dozer troubles

[Bobcatdaddy]

I’ve got a 2014 Komatsu d37ex-23. 3200 hours roughly.
When you put joystick forward it immediately turns right for a second maybe 2. After that it does great until you switch to reverse and it does the same thing. So each time you switch directions it does that. Everything else seems to be just fine. Changed hydro filters and noticed some small brass particles in it.

Sound like pump going out or something else?

 

[Jamie Pennington]

Have you figured out your issue for turning to the right.
I have a similar issue. Komatsu D39EX-21A 2006 year model with 5700 hours. This unit will start one track first, but only after a forward to reverse or reverse to forward movement. It will start one side or the other (it changes which side will start / you never can guess which one ). We have changed the PCCS steering lever assembly already. If you are in FWD and go back to neutral. Then go back to FWD it starts both tracks perfect.
We can run the unit straight for over 300 yards and it will not deviate left or right (perfect straight)
NO active or historical codes. Also all hydraulic checks are correct with specifications in service manual.
We even monitor the output for left and right HST EPC valves and can see output signals come on. Which ever one comes on first is the track that will start first.

Questioning the HST controller issue?

 

[Bobcatdaddy]

Have you figured out your issue for turning to the right.
I have a similar issue. Komatsu D39EX-21A 2006 year model with 5700 hours. This unit will start one track first, but only after a forward to reverse or reverse to forward movement. It will start one side or the other (it changes which side will start / you never can guess which one ). We have changed the PCCS steering lever assembly already. If you are in FWD and go back to neutral. Then go back to FWD it starts both tracks perfect.
We can run the unit straight for over 300 yards and it will not deviate left or right (perfect straight)
NO active or historical codes. Also all hydraulic checks are correct with specifications in service manual.
We even monitor the output for left and right HST EPC valves and can see output signals come on. Which ever one comes on first is the track that will start first.

Questioning the HST controller issue?

I haven’t figured it out yet. I suspect something like pump failure but I would hope not with only 3200 hours. On these last few cooler mornings before machine gets warmed all the way up it will almost turn a circle. Once warmed up it’s not to bad. It’s always same track that does it on mine. I need to have it checked out and see if they can find out what it is. It’s aggravating especially when unloading off trailer. I’m fearing a pump on its way out but optimistic that it could be something more simple. Machine just has 3200 hours.

 

[Jamie Pennington]

Most of the Komatsu dozers do have a way to stall test the HST pumps and read left & right psi sensors.
Or that is out of some Komatsu service manuals.
It’s possible that you have a weak pump.

if you can get your hands on a service manual, there are codes to verify the electrical signals feeding the solenoid Valves attached to the left & right HST pumps. Could be a faulty electrical connection.

 

[Bobcatdaddy]

I’ve got service manual. There aren’t any active codes that I’m aware of. Gonna change charge filter again see what fluid in there looks like. Had a small amount of brass particles in In it when I changed it roughly 15 hours ago. Got about 8 more hours left on little job if it’ll hold up and was gonna change filter see if it’s any worse. Since it’s doing it worse when fluid isn’t at operating temp makes me think it’s a little more serious than electrical or something simple.

 

[Dozerdude2021]

I have the same issues on the same machine
2014 KOMATSU D37EX-23
What did you find out?

 

[Ty Engler]

Has anyone figured this out having similar issues with my dozer