2018 Kubota RTV-X1140 HST Failure and Rebuild with Pics

[stephengmeiner]

Tore into my 2018 RTV-X1100C w/ 2500 hours. It just stopped while driving it up a hill. Tore the HST off and discovered the pump assembly cracked. Everything else looks prefect. Crossing my fingers a few new parts will get it back to work.

 

[stephengmeiner]

Details:
2018 Kubota RTV-X1140
1225 Hrs 8005 miles

Symptoms:
In drive ranges or reverse shuddering on takeoff and low power transfer. Would not go up small inclines and had overall poor transmission performance.

Process: Changed suction rubber hose and filters symptom persisted.
Charge pressure 35psi
Traveling Side High Pressure 1500-1700psi
Attached are my initial findings I have a transmission shop for Automotive and Trucks. I will be taking this unit to the shop for the full tear down and rebuild due to having the tools and parts washers etc in house.

This is a part defect failure on the piston all other pistons on the pump are universally worn and unit doesn’t look to have any other critical wear yet. Full tear down will provide more light on the situation. Thanks for looking and input/information is welcome. Aloha

Newbee here. I just started troubleshooting my HST. Pump block is cracked. I want to test the pressures when I’m done. Where do you hook the gauge hoses up to?

 

[tabike]

The pressures are checked on the screws at the top of the plate that covers the HST. You have to change the pump body and the pistons; look for the service manual, it explains everything.

 

[Markreynolds1269]

Just wanted to drop a Thank you message. Your explanations really helped me out. I have the same issue with one bad piston. Your pictures gave me the confidence to keep going and taking pump apart. I'll let you know how it goes when fixed. Thanks again

Thanks for the post. I seem to see more and more of the single piston failures from others. That is what I am dealing with now. How did you clean up all the metal fines in the system is where I am studying so I dont get a failure from that?