So far on this case we have put a used hand pump on the steering shaft,a relief valve,and a steering cylinder.It almost impossible to steer.It happened all at once.Now I'm drawing blanks.The hand pump was used but came off from a working machine.This model does not have a power steering pump.
Durango, the 580 D TLB uses the one section of the front mounted equipment pump as a supply for the steering system. If you google the Case CE parts a page will come up where you can view the circuit, possibly the portion of the pump has failed that operates the steering. Once on the parts site just type the model hoe into the search box and choose the steering section. I did notice that the old system is also shown probably for mahines not equipped with L/Bs so click on the other type and you can look at the system. The parts site I used was Coleman Equipments site.