shepard power steering loud whining noise

[4106-123]

installed shepard powersteering a few months ago and now that the weather has gotten colder ive got some issues. 1 when its cold below say 40 degrees i can crank the bus and for a minute or so the powersteering dosent work.then it will start working and i get a very!loud roaring whining noise for about 3 minutes that slowly abates. i  sure the noise is the pump and the sound is being transmitted down the lines?, im using straight 40 weight motor oil. got the unit from nimco should i change over to dextron trans fluid?

[Beatenbo]

Some coach lines use the same engine oil they run in their power steering. I have that same whine in cold weather in other buses. I would bet 30w may be a little friendlier in cold weather. I have run trans fluid in some I run standard power steering fluid in my C3

[Bob Belter]

Ahoy, 4106,

Probably pump cavitation due to restrictive pump inlet hoses/fittings.  Go bigger on these itms and see what happens.

Enjoy  /s/  Bob

[Sean]

The whine is probably normal in cold weather.  Ours screamed like a banshee when we had 15W-40 in it.

15W-40 will be quieter than 40-weight, but still "safe" if you suffer the same power-steering pump seal blowout that I did a few weeks ago. (Read about it on several posts here: http://ourodyssey.blogspot.com/search?q=steering+pump)

ATF will be quieter still.  If you have a Vickers pump, it will run fine on either.  Some pumps require ATF.

There is no "T" in Dexron®.

-Sean
http://ourodyssey.blogspot.com

[Utahclaimjumper]

I've had Sheppard in my 06 for 8 years now and have allways used 5 weight engine oil, no problems and no whining in any wheather.>>>Dan ( also a nimco take out)

[Barn Owl]

I don't know enough about power steering to diagnose your problem, but I can tell you about mine. When my father and mother were bringing back my bus from California, my reservoir leaked until the system went dry. Unfortunately my grandfather died when they were half-way across country. Because of those circumstances there was no time for a fix and the bus was driven the rest of the way dry. When I got it the steering system had a wine that was very pronounced if it was under load. Every shop I talked to said that if it was run dry then the seals where shot and it was only a matter of time before it would quit. I drained out the ATF and replaced it with 30wt by Luke's (US Coach) recommendation and continued to use it for about a year. The heavier wt oil helped. On my final trip last year, it got noticeably louder, and it would aerate the oil till it would froth out of the reservoir. It also lost almost all of its assist. I purchased a used pump from NIMCO, but because of several house projects and cold weather, I have not installed it yet. I have heard from several shops that NIMCO is extremely good at standing behind their parts, so if you have any doubt I would call and talk to them and see if a replacement is recommended.

Laryn

[TomC]

I use 15W-40 and it does whine when cold and can hear it faintly when warm.  The rebuilders specifically called for 15W-40 over ATF.  Good Luck, TomC