[johnkosir]

Every Newell is different
712 built Nov 2004 DD 60 series ZF steering
gold hydraulic junction block 
For sure no low fan, high fan when solenoid denergizes @ around 210 on silverleaf, off at 195, allways towing 20,000 lbs stacker, never have had problems overheating,  but I limit throttle to 15 gallons a minute on hills and manually down swift so the transmission won't hunt
I lost my power steering in Ocala on the way home 2 years ago and Richard came up and helped me patch it up to get it home, we both though that I probably damaged something when the solenoid valve for high fan come loose and I lost my hydraulic oil, lost power steering about 600 miles later, when steering started to fail, I pulled over at the next rest area and checked hydraulic oil it was ok, I don't think any had leaked out, was 9:00 at night and I did not feel like dealing with it then, when I got up it the morning there was  3 gallons of hydraulic oil on the ground.
We were able to patch it up so I could drive it home with no power steering, it was a challenge, but doable a lot of effort for gentle curves on the interstate, and very very difficult to get in and out of rest areas and truck stops. I never had any power steering it did not matter if motor was hot or cold fan motor on or off. 
Because of Jeffs post on accumulators I checked my accumulator pressure, it was 40 psi, it still was turning the back wheels properly when I backed up, because accumulator is hazmat no one would ship it across the border, so I charged up my 20 year old accumulator up with nitrogen and had a new one shipped to Florida, it is still holding pressure I checked a week ago I am a refrigeration mechanic so I always have nitrogen and the pump to add oil with me so changing it will not be a problem. 
712 has a piston motor with a brass wobble plate for the fan motor, After many calls to Newell and Hydraquip, I was able to figure out that it was the fan motor by capping the 2 lines to the fan motor, Newell told me to put gauge in series with the hydraulic line to the steering box to check for pressure, (did not have to do this because 712 had a gauge in the distribution block, the gauges would eventually leak so Newell stopped putting them in)  nobody told me there would only be 500 psi pressure until you turn the steering wheel it took me many tries to figure this out, when you think about it, it makes sense. Probably like a pressure washer and the block unloading if nothing is calling for pressure with the fan being priority if there is not enough volume. This is just a guess if I am wrong can someone please correct me. I finally tried the steering wheel with the lines capped and found that I had power steering, so I took the fan motor and overhung load adapter apart, the front seal for the load adapter had distorted so much that it blew the spring out of it and the lip was no longer touching the shaft that it was supposed to seal against, the back seal was damaged, the seal between the motor and the load adapter was hard as a rock. The wobble plate had small gouge in it, was only 0.003" deep (months later I bought a surface plate for something else and was able to measure it, it had some deep groves that were part of the design that I thought were damage, It was $500 if I had of known I would of ground 0.003" off it on my surface grinder and got it lapped) but I think it was enough for the motor to bypass so much oil that the return line could not handle it and distorted the front seal causing it to leak, and put the block into fan priority, and loosing power steering.
 Replaced the wobble plate, had the end of the piston that rides against the wobble plate lapped, changed the seals, put it all together and it is still working