It started about 3 weeks ago. I drive my truck about 75 miles and i begin to hear a whining noise (changes with steering wheel turn). The noise becomes constant (i hear it while driving on freeway). I feel it in brake pedal when noise comes in. This noise only happens when i have driven truck 70 miles or more at high speeds (75 mph or more). Anyone else experience this?


mike

Mike........I had simililar experiences with mine when it was newer. It happened only on extended drives at high speed during hot weather, but I only noticed it shortly after exiting the freeway.....like at the first turn off the exit ramp. At first I thought it was the transmission, but then I noticed it was connected to the steering and braking.


Now that I have a few miles on it, I have not noticed that noise, but maybe it only does it when the outside temps are higher. I have run those speeds in cold temps for 3-4 hours at a time and I don't recall any whining other than from my passenger........http://www.dieselplace.com/forum/smileys/Cry.gif

I just drove 1,100 miles from Seattle to Central California. In the upper 80's in CA and I noticed if the AC is running and I slow down quickly, I get a noise that sounds like gears winding down. My thought is I am hearing the AC compressor slow down as RPM's drop. I also noticed if I'm in high idle mode at 1,250 RPM with the AC on, the engine idles really rough. If this continues into the summer, I'm going to have the dealer check the AC system.

Had simular experience when getting back onto the fwy when the wheel is turned as I accelerate on the ramp. Thot I was running on tractor cleat impressions on the pavement ~ seem to go away once streightened out and up to fwy speed. BTW, it occurred during a cold snap when passing thru NM & AZ.

What does the fluid look like? Smell? I'll have to look and see if my '02 has a P/S cooler (my '97 has one - a steel tube right behind the grill). Sounds like a heat issue, or air (don't see how that could be, though). Might be worth changing the fluid.


I checked mine - no cooler. Removed the P/S dipstick - fluid looked dirty brown and smelled like burned ATF (I have 35K on the truck). I have no idea what the recommended fluid looks like new, but suspect not like that. I think that I need to attend to mine. Wouldn't be surprised if the fluid temp exceeds 230 degrees at times.Edited by: Horse Trainer

I have had the same deal, long drive, cruising at 75. Turn the whell lock to lock and it rally whines. Only happened a coupel times.

Mike L.


I also get this. It's the same time as your talking about but it's not the power steering pump on mine but rather the turbo spooling down.


See this link:


http://dieselplace.com/forum/forum_posts.asp?TID=6856&KW=Mike330R

Mike L I get this problem aswell, But I thought it was because my truck is lifted with 37s, but it does happen after long drives in warm/hot weather, but it is only when I turn the wheel lock to lock.

I finally took mine in yesterday and had a mechanic drive it. Turbns out he thinks the power brake booster is not working right.





We will see in a day or so ;(

Mike330R


I buy that diagnosis. The power steering and brakes work off the same pump. When my noise comes in i can make it louder by depressing brake pedal. I also have noticed my ABS getting a little overactive. This could all tie in. I knew someone here would come up with something.http://www.dieselplace.com/forum/smileys/Approve.gif

Turns out mine was a bad brake hydro boot unit.


Replaced it but I have not been on a long enough drive to test it. The brakes do feel tons better. I alomst went through the windsheild when I first used the brakes with the new part.

Mike, our pumps should not wine. If it was mine I would flush the system. I would also use Synthetic. Use the same procedure as when changing all 13 quarts in the Allison. We did this to my son's Dodge with good results. Later! Frank

Frank


Thanks for the input and i agree with you. Problem is the truck has 4K miles, and that is not enough time to contaminate the fluid(by the way, it looks new and smells sweet). We are also talking about the brake system here, nothing to be trifled with. I will contact Robert (GM tech i have never met but heard a lot about from people that i respect) and have him handle it. I need to get his butt over here so he can contribute some of his wisdom.


mike

Sorry, didn't see it was an 04. I would let the dealer fix it. My 02 has 44K and I plan to do mine. The power steering fluid really works hard. I posted a question before on what the service life is but did not get a reply. Maybe Sperry-Vickers or is it Sperry-Rand now a days can tell me. Vickers invented this pump back in 1935 or so. Later! Frank

Mike,


I had my power steering pump replaced today. No more whine!


Did you fix your problem?

Mike, our pumps should not wine. If it was mine I would flush the system. I would also use Synthetic. Use the same procedure as when changing all 13 quarts in the Allison. We did this to my son's Dodge with good results. Later! Frank

Never saw synthetic PS fluid. What did you use?

Jim