2003 M1123 Power steering refill.

[Mattguy]

I've tried reading everywhere about filling of the power steering reservoir. Every TM I've read shows the power steering pump attached to the front of the truck. I unscrewed the top brass fitting and filled to the glass site on side. Is this the correct way to fill it?

 

[Maxjeep1]

I've tried reading everywhere about filling of the power steering reservoir. Every TM I've read shows the power steering pump attached to the front of the truck. I unscrewed the top brass fitting and filled to the glass site on side. Is this the correct way to fill it?View attachment 859781

I took that lid off to add fluid. There is a filter underneath the lid also.

 

[Mattguy]

I filled it up with removing the brass screw on top, but after running for a while it started pouring out the top. So I assume you fill it without truck running.

 

[Maxjeep1]

I filled it up with removing the brass screw on top, but after running for a while it started pouring out the top. So I assume you fill it without truck running.

I thought that brass elbow just spun. You take the lid off and it makes a little more sense. You can see it better and and filled it 3/8” below the top.I was going to change the filter and flush it but fluid was clean so I will wait.

 

[Mogman]

Yes that is what the sight glass is for, you do not fill it while running, if the vent system was working and the top was sealed it should have overflowed into the vent system which is not good, is it noisy as in it has air in the system?
Edit, review the applicable TMs

 

[Action]

I thought that brass elbow just spun. You take the lid off and it makes a little more sense. You can see it better and and filled it 3/8” below the top.I was going to change the filter and flush it but fluid was clean so I will wait.

Yeah. You should check out the TM in regards to fluids n such or you are going to end up with dexron in everything.Unless your steering reservoir vent just runs up in the air.

And fluid level rising is likely air being purged.

 

[Mattguy]

Yeah. You should check out the TM in regards to fluids n such or you are going to end up with dexron in everything.Unless your steering reservoir vent just runs up in the air.

And fluid level rising is likely air being purged.

I tried finding TMs on the m1123 power steering system but all I found was the power steering unit with reservoir attached.

 

[Action]

Fluid FULL is at center of sight glass. Bleeding procedure is same for all, as far as wheel turning and such.
Once all air is bled, i just use paper towels to suck up and extra fluid.
Adding and removing fluid is easier by just taking the lid off. And, a standard screwdriver is more readily available than a large wrench or crescent wrench for that brass nut.

 

[Guantanamo George]

Fluid FULL is at center of sight glass. Bleeding procedure is same for all, as far as wheel turning and such.
Once all air is bled, i just use paper towels to suck up and extra fluid.
Adding and removing fluid is easier by just taking the lid off. And, a standard screwdriver is more readily available than a large wrench or crescent wrench for that brass nut.

OK... fitted a new 6.5 N/A and 4L80E. Everything is fine except a whine noise coming from the Power steering system( new style with remote reservior) System is bled correctly with no leaks, air or foaming issues. I put it down to power steering pump. Fitted new pump and whine is still there. Thought it might be a problem with the fluid as I used dex111 power steering fluid. Have checked different manuals and some say use dex 111 but TM 9-2320-387-10 says to use DexV1 which is a full synthetic. Any problem just using DexV1 ATF ?

 

[Coug]

DEX VI is a little thinner, and GM says not to use it in power steering or manual gearbox applications.

That being said, it's what the military is using.

You might still have some air in the system, or might have an air leak letting air in.
It might be one of the other components, but unlikely.

How long have you run it with the new pump? I had the old style with pump/reservoir together, and it wouldn't bleed out following the procedure in the book. Finally overfilled it, cranked it and spilled the excess onto the ground. Turned it off, filled to overflow again, and drove it. Whine finally went away, and level was only a little high at that point so I left it. That was 8k miles ago.

 

[Guantanamo George]

DEX VI is a little thinner, and GM says not to use it in power steering or manual gearbox applications.

That being said, it's what the military is using.

You might still have some air in the system, or might have an air leak letting air in.
It might be one of the other components, but unlikely.

How long have you run it with the new pump? I had the old style with pump/reservoir together, and it wouldn't bleed out following the procedure in the book. Finally overfilled it, cranked it and spilled the excess onto the ground. Turned it off, filled to overflow again, and drove it. Whine finally went away, and level was only a little high at that point so I left it. That was 8k miles ago.

Haven`t run it long with the new pump...maybe 5 miles. Just ran the part number on the new steering pump I installed and it is the latest pump for the 6.5 TD. (120bar) The pump that should be fitted is the older version rated at 107 bar which is for 6.5 NA with 4L80E. Is it possible that the pump that I have puts out too much pressure or possibly something to do with the pressure relief valve? I have changed the fluids again...bled the system again and still have a whine.

 

[Action]

delete

 

[Retiredwarhorses]

The 120 bar pump is for the Shepard steering gear…both of them whine regardless

 

[Guantanamo George]

The 120 bar pump is for the Shepard steering gear…both of them whine regardless

So whining is common with this style pump and not necessarily a fault ?

 

[Retiredwarhorses]

So whining is common with this style pump and not necessarily a fault ?

Correct, but that pump is not for your application steering gear, so it could be causing an issue I’m unaware of.

 

[Guantanamo George]

Correct, but that pump is not for your application steering gear, so it could be causing an issue I’m unaware of.

The first pump I removed was the earlier 107 bar version and it whined even worse than this new one. Do you think that there is any benefit in changing from the power steering fluid that I am using to the Dex V1ATF which I believe is thinner . If I have to put up with a whine I want to get it as quiet as possible. Thanks very much for the input.

 

[Action]

The first pump I removed was the earlier 107 bar version and it whined even worse than this new one. Do you think that there is any benefit in changing from the power steering fluid that I am using to the Dex V1ATF which I believe is thinner . If I have to put up with a whine I want to get it as quiet as possible. Thanks very much for the input.

Why are you using power steering fluid?

 

[Guantanamo George]

Why are you using power steering fluid?

Why are you using power steering fluid?

Because a so called expert told me that the specs of power steering fluids are far greater than any ATF. My fault for going against what my gut told me. So should I be flushing the system and adding dex V1 ATF ?

 

[Coug]

If you flushed the system when you replaced the pump, there is no reason why power steering fluid shouldn't work.

 

[Mogman]

The power steering/brake/winch/fan system is an "open" hydraulic system, meaning there is fluid flowing through the system at all times, the only time you normally ever force the pump to bypass the 1550psi (107bar) VS 1750PSI (120bar) is when the steering is at lock (why the belts squeal on a V belt anything when the steering is turned to lock) or if Godzilla steps on the brakes and possibly with a winch at over full load. steering may feel "lighter" because the newer pumps usually have a higher flow and the valving in these pumps actually senses when demand is put on the pump increasing flow so the newer pump may be more responsive. otherwise it should work fine, I would not make a habit of turning the steering to lock and keeping it there, but that goes for ANY PS system.