I used ATF instead of fluid that met LR specs when unable to get to purchase the correct fluid, as recommended by the mechanic at my local garage. I needed to replace the seal on the input shaft which suddenly leaked very badly. The fluid in the rack was flushed multiple times when trying to use hydraulic pressure to push the seal block right out.

A road test after finishing revealed extremely stiff steering operation which persists even with the vehicle on stands with no weight on the wheels. The stiffness is slightly worse with the servotronic transducer electrical connector removed. There was no stillness during the multiple full left to right movements when trying to use hydraulic pressure to force out the seal block.

It seems that the piston in the rack is binding as though the seal material has been affected by ATF.

Can anyone comment on whether or not ATF is incompatible with the seals in these racks?

Replacing the ATF with Penrite PAS001 which is sold as meeting the LR specs made no difference. However after spotting the absence of turbulence in the half-full reservoir at idle and only minimal turbulance at high engine revs, I found that at high engine revs the steering weight was about normal for slow speed driving indicating that the pump is under-performing. The reservoir's filter flow will be checked tomorrow which I hope to be very low indicating that the filter is blocked.