HST drive issue

[D100jj4]

Hst drive issue.
I’ve got a Kubota L48.
I have recently changed hst oil and filter. Still having same issue.
Unit will work but is really slow. After about 20 to 30 mins unit will no longer move. I can pick up front and rear where tires are off the ground and tires will roll forward or reverse but no power to move machine. Unit worked better when it was really cold out. I used Mobil 424. Should I put a thicker oil in unit or do I have another issue. Hoping I don’t have to get pumps rebuilt. Implements are working fine. Bucket and backhoe aren’t lacking in power.
Unit has 2000 hrs. Bought last year.
Does anyone have any thoughts?

 

[rbargeron]

Hi - I have an L48 too. HST units rarely fail. Often there's something loose or disconnected in the linkage under the floorboard. Very doubtful its related to using Mobil 424 fluid.

For no-drive symptoms, the main clutch might be slipping. Check the free play in the pedal linkage (see attached). Also check for normal resistance and range after using up the free play. A slipping clutch can prevent all drive. Other hydraulics work ok because they use pumps mounted on the engine.

If linkage and clutch check out, pressure testing the charge pump in the HST might be needed, using a 750 psi gauge adapted to British Straight threads. Dick B

 

[North Idaho Wolfman]

Yea I'll second the clutch being burned out.

 

[D100jj4]

Thanks you guys for the help.
I will check the clutch and go from there.