I'm ready to fill up the PS system on my project Excursion. Owner's manual says to use straight Mercon, and not to use anything dual-use. Went shopping, and didn't find anything that was straight Mercon.

So I fired up the Internet and searched around for a while, and results were all over the place. Mobil 1 synthetic seems popular, but no one seems to carry it around here. They do carry Valvoline MaxLife labeled as Dex/Merc/Mercon LV- and found a couple people using it.

I've also found people using Mercon V.

So what should I use- that I can go out and get locally?

 

I am running all synthetic Rotella T6 oil in mine, 5W40, which I get at my local parts store.

 

Isn't that motor oil? I'm talking about the power steering system.

 

Sorry, I miss interpreted what you needed. I read PS as Power Stroke...

 

I did a pump replacement on my V10 last November and used MerconV. No issues since. Walmart has the Supertech brand, cheapest I found.

Make sure when you fill it to raise the front tires off the ground and turn the wheels back and forth to bleed the system. Key On Engine Off.

Mobil1 ATF is compatible with MerconV.

Transfercase XL-12 is essentially Mercon but more expensive from Ford.

 

I just did a pump replacement about 1,500 miles ago and no issues here using MerconV.

 

Don't let any fluid labeled "Dex/Merc/Merccn LV" anywhere near the two Fords listed in your signature.

That's the one you want.

Stewart

 

You can run a motor oil in there if you wanted. I've ran almost all types of atf in Ford power steering systems. Hydraulic oil works also.

It's just a pump and a cylinder basically. In some of the heavy machines at work we run a 10w30 in the hydraulic systems, idk why it's in there, but it's been there for years. Lol

 

Please elaborate ...

 

Case skid steers use 10-30 WITH there Super Secret additive.

 

This is true. You may have some additional shearing, but it's just a hydraulic system...

Transmissions and Limited Slip Differentials have clutches in them and need friction modifiers and whatnot in their fluids.

 

1st if not already done replace the power steering resivor with a new oem unit. It's about $20 shipped to your door. Why you ask, well there is a fabric filter in it that gets gunk in it. No sense putting clean fluid in a dirty resivor.

Had a whine in my Ex that has 220,000 on the pump and PS system. I put amsoil trans fluid in it....Flushed about 5 qts thru it and whine went away. So I guess that is a good thing. I recommend Amsoil, but other synthetic mercon compatible atf will probably be just as good.

Note on XL-12, I have 4 bottles of this for my transfer case. Did not use it because in a 4x4 the XL-12 can mix with the transmission fluid. So I put amsoil in both so I would not be mixing fluids.

 

I put in Mercon V in mine last year. All good and no complains. Didn't know the res. has a filter in it though, good tip!

 

I'm pretty sure the point Stewart was making was that the LV should never ever find its way into a 4R100 trans, which Joey has 2 of. So he was saying to use the MERCON V, the same fluid those trans use, that way you don't end up with a bottle or two of the wrong fluid sitting around that could someday be accidentally used to top off the trans. Either LV or V would work in the PS system but why invite potential future issues by having the non-common fluid sitting around?

Thanks for the good tip on the new res idea Rock!

 

This is true as well and keeps things simple.

When you do transmission work involving fluid change, also work on your power steering system. Same fluid in both.