No lift no steer

[Mobil mech]

Ii have a John Deere 2240 hydraulic have a mind of their own. May or may not work when I start tractor. If they do work they work as long as tractor is running. But if cut off and restart then they won't work. Checked sump screen. Checked pressure at power steering T only had 100lbs. Remove hydraulic filter and cranked tractor over to see if trans pump was working. Seemed to bemoving plenty of oil. Reinstalled new filter. Checked reliefs at filter found no problem. Replaced stroke control on main pump. Same problem. Blocked pressure line at steering T didn't raise pressure. Do I need to rebuild high pressure pump?

 

[Tx Jim]

Have you checked frt hyd pump drive coupler for pump shaft slipping? Did you try adjusting stroke control screw all the way in? If you have go psi & flow from trans pump to frt pump and the 2 previously mentioned things have been done then I suppose frt pump requires dis-assembly & inspection.

 

[Zebrafive]

After doing Tx Jim's suggestions the only things I can add is check the check valve in the steel line from the transmission to the front pump (only without Reverser or HI-LO trans). Replace the filter in the front pump it's for the stroke control valve. It could be R27173, or R68681 depending on your serial number.

 

[Tx Jim]

I suppose the trans oil level is at the full mark?