HST issue

[OlFerguson]

Hello.
I have a x1120 thats giving issues where it will not go forward or reverse. I have checked the pressure on the HST ports and I am not getting anything for pressure. When i pulled the shaft cover joining the hst to the drive box/engine it was not engaging at any rpm. Just wondering if anyone has had this issue and if it was an easy fix like a pressure valve, or will a guy have to pull the entire transmission out for an overhaul. Thx. Machine is low hrs.

 

[whitetiger]

Hello.
I have a x1120 thats giving issues where it will not go forward or reverse. I have checked the pressure on the HST ports and I am not getting anything for pressure. When i pulled the shaft cover joining the hst to the drive box/engine it was not engaging at any rpm. Just wondering if anyone has had this issue and if it was an easy fix like a pressure valve, or will a guy have to pull the entire transmission out for an overhaul. Thx. Machine is low hrs.

Are you saying that the shaft from the engine to the hydrostat is not turning? If so, the drive plate on the flywheel probably has stripped splines or the rivets have sheared.

 

[OlFerguson]

This shaft is not turning to my HST. What would cause that ? Thanks for your help.

 

[OlFerguson]

I’ve read on a few forums people having issues with these so I’m not sure if I should just yank the entire unit out for inspection or if there’s other ways to test other components. It will not drive forward or reverse or engage. My service intervals are impeccable.

 

[mikester]

Is this a drive by wire machine or do you have mechanical linkages to your control valves?

 

[ruger1980]

What @whitetiger said is spot on. If your shaft is not turning it is no longer coupled to the engine.

 

[whitetiger]

I’ve read on a few forums people having issues with these so I’m not sure if I should just yank the entire unit out for inspection or if there’s other ways to test other components. It will not drive forward or reverse or engage. My service intervals are impeccable.

The shaft in your picture is the hydrostat motor output shaft, not the input shaft from the engine.
Have you checked the hydraulic oil level in the tank under the passenger seat?

 

[OlFerguson]

My hydraulic oil tank is at the appropriate level on the dipstick . I’ve also checked the oil for the transmission and it’s spot on. Suction/transmission filters are brand new. My linkages are all adjusted to factory spec. I disconnected the shifter and manually tried to get the transmission to engage into forward and reverse … no luck

 

[whitetiger]

My hydraulic oil tank is at the appropriate level on the dipstick . I’ve also checked the oil for the transmission and it’s spot on. Suction/transmission filters are brand new. My linkages are all adjusted to factory spec. I disconnected the shifter and manually tried to get the transmission to engage into forward and reverse … no luck

The next step is to check your charge pressure, see attachment.