How to tell if it is the power steering pump or the steering box?

[turbo_bu]

I have noticed over the last few years that my steering isn't quite what it should be (2004 K2500). After reading a lot of posts about how bad the steering is on these trucks, and that it's bad just live with it .... I am hoping that maybe mine is just a bit worse and could benefit from some attention.

I am the original owner, and it is still on stock sized tires. I briefly did the 235/85R16's for a bit, but I am back on the stockers again. Generally, when I first start it, it steers ok, but you can tell that you are having to put some effort into the steering wheel. After driving it a while (everything warmed up), if you are in a parking lot and doing some tight steering, it doesn't feel as though you have any power assist. Normal driving down the road either hot or cold is not bad and doesn't show any issues.

I should add that the steering box was replaced under warranty after about 1 year due to a leak. It wasn't that big of a leak, but it would drip after a while. I figured they were just going to replace the output shaft seals, but they went ahead and swapped it out.

The brakes are about as good as usual. I don't feel as though I am having to put extra force into them either hot or cold. Admittedly, the brakes on these trucks have never been outstanding, but I don't think I have a pressure issue with the hydroboost.

So now my dilemma - is my pump getting worn out so when it is hot it doesn't produce adequate pressure? Or is my steering box the issue? Is there way to help diagnose which one could be causing the problem?

I would love to put in a pressure gauge to actually measure the system, but I don't have any of the fittings necessary to connect to it.

 

[Pure Diesel]

How often do you replace and flush the power steering fluid? Try putting on a power steering cooler.

 

[Ron Nielson]

Based on cost and effort, I'd change the pump. I believe that the LML pumps have higher pressure and volume, but that's something that you would have to determine. Or maybe a PSC pump.

And take a read here https://www.duramaxforum.com/threads/my-baby-is-sick-hard-power-steering.144843/page-2 Remember that this is just one person's experience.

 

[turbo_bu]

How often do you replace and flush the power steering fluid? Try putting on a power steering cooler.

I did flush out the factory fluid at ~30k miles. I put synthetic power steering fluid back in. The truck now has ~110k on it.

I am leaning heavily toward adding a power steering cooler no matter which set of parts I end up swapping.

 

[turbo_bu]

Doing some more troubleshooting on this truck. Trying to measure the fluid temperature using an infrared heat gun. Anyone know how hot is too hot???

 

[2004LB7]

I did flush out the factory fluid at ~30k miles. I put synthetic power steering fluid back in. The truck now has ~110k on it.

I am leaning heavily toward adding a power steering cooler no matter which set of parts I end up swapping.

Your power steering fluid is well beyond it's maintenance interval. Why don't you try changing it first

 

[JSimmsy]

If I were you, I'd start with a fluid flush. Then go to a pump/cooler upgrade.

If there's no slop in your steering or leaking from the box, I doubt it's the steering box.

I've went though several boxes and pumps on my LBZ. Currently running a blue top that seems to be developing some play in it. I've done the LML pump upgrade once and even it died after some years. Went with the PSC pump this last time about a year and a half ago and by far the best results.

 

[turbo_bu]

Your power steering fluid is well beyond it's maintenance interval. Why don't you try changing it first

Out of curiosity, when are you supposed to change the power steering fluid? I looked in the owners manual, but didn't see it listed.

 

[Ron Nielson]

I would change every 2 years or 50K miles, assuming no problems. For several years, I would suck out the power steering reservoir and replace it when doing oil changes. The idea was that SOME new fluid was better than none. I don't think I have kept to that very well.

 

[2004LB7]

I think it's something like 30k miles or two years. I'd do it on the brake fluid schedule

You can do the easy way with a turkey baster and suck out and refill several times with running it between until it looks clean. Or disconnect the return hose and pump it all out while keeping the reservoir topped up. Your choice

 

[turbo_bu]

Is this schedule for regular power steering fluid? What about synthetic power steering fluid?

 

[JSimmsy]

I "think" most people do not run synthetic. I know I don't. You can do some research on that topic.

ACdelco fluid is a good option. Especially since it's actually clear and if your doing a flush and using a clear 3/8" hose to a bucket or pan you can actually see in the tube when it's clean fluid through everything.

 

[2004LB7]

Is this schedule for regular power steering fluid? What about synthetic power steering fluid?

Synthetic still suffers from shear, even if less then conventional oils. But more importantly they will load up with contamination at the same rate. And the steering system has no filter like an engine. The best use of synthetic in a steering system is the better viscosity stability at temperature. But I wouldn't think it would be too wise to extend the use much more then conventional.

Just use the same ATF you use in your transmission and it will eliminate another oil you have to stock up on. Maybe change it at the same time when you do the transmission fluid

 

[DAVe3283]

X2, just use ATF. Switched all my vehicles from "real" power steering fluid to ATF years ago and haven't noticed any change in steering, good or bad. But like Jason says, it is one less fluid to have to keep on the shelf.

 

[Dozerboy]

I use synthetic PSF because I had issues with foaming and it puking oil when I go up north in the winter. 200k and 17 years is still alive

 

[turbo_bu]

X2, just use ATF. Switched all my vehicles from "real" power steering fluid to ATF years ago and haven't noticed any change in steering, good or bad. But like Jason says, it is one less fluid to have to keep on the shelf.

I've heard of using ATF, but also heard that ATF isn't "compatible" with the seals in the system. In the past I have used ATF in a pinch, but have tried to stay with the correct fluid if possible.

As for using synthetic PS fluid, it was only as a band-aid to try and help the system. I did the flush / swap years ago based on some early Duramax experience which said that it helped with the firmness of the hydroboost. Right after I did the swap, I did notice that my brake pedal felt firmer. Not sure if anyone has noticed a difference in "feel" with ATF vs. powersteering fluid.

 

[LBZ]

Do you experience a chatter that you can kinda feel and hear in the steering wheel when turning in a parking lot once the oil is hot?

 

[turbo_bu]

Not so much chatter, but the steering gets a lot harder the farther that I turn it and there are times I here whining and popping sounds. FWIW - I have been trying to do some diagnostics with it by steering back and forth right after I start it, then doing it again after I have driven ~20 miles. It appears that the steering is weak both cold and hot.

I have had power steering pumps in older trucks (think 80's) where the pump and belt would squeal. This truck doesn't do that.

 

[JSimmsy]

It really sounds like your pump is going bad. Like I said before, I've used all of them in the past and I'd highly recommend the PSC pump and be done with it.

I use a vacuum pump to get the initial air pockets out. Then I've used Driven Diesel's procedure for bleeding after that. Works great for me.

 

[fajitatone]

my steering has groaned and vibrated the wheel since I got it in 2006. I'm about to change pumps and lines. I want to avoid the steering box. it the groan pump noise or the steering box?