Power Steering Reservoir Filter

I spoke with Jim Malcom, Presost Service Manager, Southern region. He stated that changing out the Dexion III to motor oil was recommended and practiced by Prevost. He also stated that if driving in the southern areas of the US, he recommends 30 weight motor oil. If driving in the northern areas, he would recommend 10 weight oil. He stated that 20 weight is a good compromise and works good.


He will look up the technical information concerning the motor oil recommendation and forward that information to me. When received, I will make it available to all.

Thanks for bringing the topic to light, I have the power steering fluid change out on my list.


Hector

I've been reading this thread for a couple of days and I'm just wondering why would anyone change their power steering fluid from Dextron III to motor oil. What is the advantage? Surely it's not a cost issue or supply problem. If there is some unstated advantage, let's hear it. Otherwise, why the heck would anyone switch???

And as long as Ted is getting hardnosed about this, I want to see the approval to run oil in writing. Especially the part about oil types and weights.

The service manager says 30 is good, but if its cold 10 is better so why not use 20? Sounds like a real technical bit of solid advice.

Except for grasping at straws to placate owners who hear noises what is the reason for using oil? And just to beat this dead horse a little more, now that it is OK to use oil has the factory revised the label on the side of the reservoir to reflect the use of oil or are they waiting for the inventory that says to use Dextron III to run out before it is reprinted to say whatever weight oil you want to use is OK.

I have made a few calls to see what I can learn. First I called Vickers because I believe that is who manufactures the pump. I got voicemail and am waiting for a call back.

Then I called Shepard, that is who I believe makes the steering box. TRW also makes them and if someone is aware of the TRW box as what is being used please correct me.

I spoke with a Shepard service tech and asked him the fluid preference and he laughed and told be that was a sticky topic, no pun intended. At one time they used to recommend and 10-40 BUT received much grief from manufacturers of equipment using their boxes because those folks recommend power steering fluid and in an effort not to confuse they changed their policy to suggest using whatever the manufacturer suggests.

I then asked why they prefer that the motor oil should be used. He said that it holds its viscosity better and the seals last longer keeping in motor oil. He went on to say do not ever put Dextron 6 in because that will for sure eat the seals but other than that the steering box will function with any fluid in it short of dirty water.

When I get a call back from Vickers I will also post what I learn.

He also said 100000mile service interval. So there you have it. I have the red stuff in mine and am experiencing a small leak at the pump around an O-ring. When I get around to it I may try changing the fluid to motor oil to see if it stops as that would be easier than getting to the o-ring and could give definitive reason as to the use of one fluid for another if it were to stop that leak. That is only of course if Vickers gives me the same responce as Shepard.

OK ladies and gentlemen....here you have it. The definitive answer. We can use Dextron III, but if we use motor oil use straight weight 30 unless its cold, use 10 weight, so we can compromise and use 20 weight, unless you want to use the 10-40 Shepard recommends.

Did everybody get that?

I'm thinking of running extended life power steering fluid. Anybody have an opinion on that we can discuss?

The label on the side of the reservoir and the fluid specs in the owners manual do not mean diddly so apparently whatever you want to put in your power steering is OK, and if it is not listed here, we will find someone who says its OK.

I will reserve my opinion until I here from Vickers.

I do remember Cat telling me to use motor-oil and I did that for the 12 years I had the truck. Peterbilt says use power steering fluid. Whos advice should I have taken? The folks who built the truck or the folks who built the engine neither being the one who manufactured the pump or steering box:confused:

I understand and respect Jons opinion to follow manufacturers directions to the letter. I do not think you could go wrong using what is labeled on the reservoir.

I am just trying to get information to add to the discussion from the folks who actually manufactured the components.

Sheppard includes motor oil on the suggested list of lubricants on their website.

Where is Orren with his 2 cents?

My Liberty is 14 years old and has nice clean red stuff in it and will stay that way. How the hell would you get all the Dextron out of the system anyway?:(

Remove the return line from the reservoir start the bus and pump it out. You arent going to hurt the oil by mixing it with a little trans fluid. That is an old trick I have been doing for years to keep my V-8's clean. Put some into the crankcase the day prior to changing oil, it is VERY HIGH detergent stuff. Also makes great hand cleaner.

OOPS! Put that in the maintenance log Trukster, changed it about 2 years ago. :eek:

OK Mole Man, I'll update the log and thanks for the fluid change!