Technical Service Bulletin Question?

[adz55]

I have a 2007 GMC Sierra 1500 4x4 ex. cab 5.3L. Ever since it was new I've experienced a noticeable whistle/whine when driving straight at moderate RPMs, but not while turning. (for more details check out my earlier thread: http://www.gm-trucks.com/forums/index.php?...=78992&hl=)

 

After many trips to the dealer I was finally able to recreate the noise while parked to show it to them. They said they figured out the source and found a technical service bulletin on it that acknowledges the problem but they don't have a fix yet. The service rep couldn't give me any details on the source of the problem, or what the TSB says. Can you tell me more? This is driving me crazy.

 

Thanks!

TSB# 1974648

[Stylous]

I have a 2007 GMC Sierra 1500 4x4 ex. cab 5.3L. Ever since it was new I've experienced a noticeable whistle/whine when driving straight at moderate RPMs, but not while turning. (for more details check out my earlier thread: http://www.gm-trucks.com/forums/index.php?...=78992&hl=)

 

After many trips to the dealer I was finally able to recreate the noise while parked to show it to them. They said they figured out the source and found a technical service bulletin on it that acknowledges the problem but they don't have a fix yet. The service rep couldn't give me any details on the source of the problem, or what the TSB says. Can you tell me more? This is driving me crazy.

 

Thanks!

TSB# 1974648

 

Hmmm...I'll throw in my .02 but I am referring to my Truck ('02) that had the same problem. A friend of a friend who works for Chevy stated it was the PSP but that there was nothing "wrong" with it. He suggested I put in synthetic PS fluid (valvoline) and that should stop it or at minimum quiet it down.

I did just that and the sound did go away. The synthetic fluid is also better for the hydro boost unit as well I'm told.

 

May be worth a try , it only cost $6.00 for one quart, you'll need two to fush out the old fluid.

[adz55]

I'll try that, but I'm curious about what that TSB says...

[Stylous]

I'll try that, but I'm curious about what that TSB says...

 

I found this on a Chevy forum after a google of the TSB you listed...same solution I tried.

 

Document ID# 1875699

2006 Chevrolet Chevy K Silverado - 4WD

Subject:Power Steering Whine Noise - keywords fluid gear hose idle pump turn #PIT4208 - (12/04/2006)

 

 

 

Models:2003-2007 Cadillac Escalade, ESV, EXT2003-2007 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe2003-2007 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon XL Denali2003-2007 Hummer H2

 

 

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Some owners may comment on a power steering pump whine noise. This whine noise is most commonly heard between idle and 2000 rpm coming from the power steering pump.

 

Recommendation/Instructions:

Reports of flushing and refilling the power steering system with Valvoline SynPower Power Steering Fluid have reduced or eliminated this noise. Valvoline SynPower Power Steering Fluid is a synthetic fluid and is available at most auto parts stores in quart size containers. In most case 3 or 4 quarts will be needed to flush and fill the system.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[adz55]

I'll try that, but I'm curious about what that TSB says...

 

I found this on a Chevy forum after a google of the TSB you listed...same solution I tried.

 

Document ID# 1875699

2006 Chevrolet Chevy K Silverado - 4WD

Subject:Power Steering Whine Noise - keywords fluid gear hose idle pump turn #PIT4208 - (12/04/2006)

 

 

 

Models:2003-2007 Cadillac Escalade, ESV, EXT2003-2007 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe2003-2007 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon XL Denali2003-2007 Hummer H2

 

 

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

 

Condition/Concern:

Some owners may comment on a power steering pump whine noise. This whine noise is most commonly heard between idle and 2000 rpm coming from the power steering pump.

 

Recommendation/Instructions:

Reports of flushing and refilling the power steering system with Valvoline SynPower Power Steering Fluid have reduced or eliminated this noise. Valvoline SynPower Power Steering Fluid is a synthetic fluid and is available at most auto parts stores in quart size containers. In most case 3 or 4 quarts will be needed to flush and fill the system.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

 

Awesome, thank you. I also found this thread with the actual TSB I was referring to:

http://www.gm-trucks.com/forums/index.php?...mp;#entry592089

[adz55]

I took it in again today, easily reproduced the sound (it's been getting louder), and they are now replacing my rack/pinion (steering gear) under warranty, and possibly the pump as well. I'll let you know.