As RickB points out, the PS is a separate pump and isolated system on the TC35. However, the same gear drives both the main hydraulic pump and the PS pump right off the engine. I think if there was a gear problem, you'd hear a noise, unless the drive shaft is sheared. Also, if you raise the front wheels with the FEL, you should be able to turn the front wheels with the steering wheel because the steering motor is made to back-pump. That way, if you ever tow the tractor, you will still have steering, though very hard. I think there is a good chance one of your lines is plugged and the PS pump is not getting fluid. That goes back to RickB 's first analysis and the pump would act like the reservoir is empty. Another issue might be that the PS cylinder has blown internal seals and fluid is bypassing from the extend to the retract side. If you raise the front wheels and can easily move the tire left/right, then there is a chance the cylinder is at fault.