02 power steering noise

I have an 02 pre-runner with 335,000 miles that just started the good ole'
Power steering whine.
First thing I did was change the fluid numerous times including cleaning the screen at the bottom of the reservoir .
Didn't help much.
Put a whole new power steering pump on with the old reservoir and screen appeared clean enough .
Didn't solve the problem and the noise is loud as ever .
It's steers perfectly and the noise doesn't seem to have a negative affect other than it's way too loud . Fluid flow through the reservoir doesn't seem to be moving with the volume I would expect.
Still some kind of a re-striction ?

 

Rack?

 

When does the noise occur - while turning? While driving straight and without turns? At idle? There's not much to the power steering system that would cause noise:

1. The drive belt could be slipping. Usually causes noise only when you put a load on the steering system by turning the steering wheel. Consider replacing it.

2. Pump going out. You wrote that you installed a whole new power steering pump, so unless it's not really "new", I would suspect the rotor in the pump is wearing against the pump housing.

3. Did you thoroughly clean all of the dirt from the screen at the bottom of the reservoir? You should be able to see light through the entire screen; however, I wouldn't suspect that to be the cause of your noise.

4. The rack could be going out and causing some noise when turning.

Take a look at Timmah's 44-minute long video to get an idea on what a clean screen looks like and also how fast the pump cycles the fluid.

 

The noise is all the time and proportionate to the RPMs.
The new pump is an OEM unit. It does not get louder when you steer or turn the wheels.
The truck steers perfect.
I'll check out that video .

 

One more thing that, when going bad, fits your descriptions is the idler pulley. I don't know anything about your particular engine installation but I'm assuming you have a V6. With 300,000+ miles on the truck the bearing in the idler pulley (or the entire pulley) must have been replaced a couple of times.

The pulley assembly with bearing costs somewhere around $50, but the bearing itself can be had at a motorcycle shop (or bearing shop) for around $4. It's worth checking out. The part number is

$17 6301-2RS Bearing - Lubricated Chrome Steel Sealed Ball Bearing - 12x37x12mm Bearings with Rubber Seal & High RPM Support

6301-2RS and the dimensions are 12mm inside diameter, 37mm outside diameter and 12mm width. RS stands for Rubber Shielded. There are 3 types, Rubber shielded, Metal Shielded, and open.

1. Remove the pulley and put it in a vice with a couple of appropriate-sized sockets.
2. Close the vice to push the old bearing out.
3. Remove the sockets and push the new bearing in with the vice.

Other than that, I can't think of anything else that would give the symptoms you are describing

 

The bearing has never been replaced.
While taking the pulley off to replace the pump the bearing didn't look bad.
I have been wondering exactly that the last few days because the noise is tending to get louder and quieter.
I will check that out next.
Thanks for your input .

 

You are sure it's the PS pump? Does it make the noise in neutral?

 

It make the noise anytime it's running no matter what and it's proportionate to engine speed.