Mild Vibration

NothinButBowTies · January 28, 2004

Ever since I bought my 03, I have noticed a vibration coming from the powertrain (Can feel it through the floor board and the drivers seat). It is really only noticeable when I am in gear or in park with my foot on brake. I took it to the stealer and in fine fashion "could not replicate." Also it realy doesnt do it when the engine is cold, only when I am at operating temperature. Does anyone have any ideas? Thanks Nick

chvythndr · January 30, 2004

I have no idea. If it's only doing it when your in gear and in park w/ your foot on the brake, the only thing i could think of is your engine mounts. But, being a '03 kinda rules that out.

NothinButBowTies · January 30, 2004

I have no idea. If it's only doing it when your in gear and in park w/ your foot on the brake, the only thing i could think of is your engine mounts. But, being a '03 kinda rules that out.

I was thinking engine mounts too. Why would you rule that out bc it is an 03? Is there a visual way to confirm the engine mounts are in good condition? Could it be a transmission mount?

Thanks for the help, Nick

Shaggnasty · January 30, 2004

y'all let me know when you figure it out...I've given up. I thought

it was transmission related.

Pioneer · January 30, 2004

Is it a constant RPM independant type of vibration that does not speed up w/RPMs?

If so, it sounds to me like something is either loose (duh) or touching the body of the truck.

If you can replicate this in your driveway, have a trusted buddy sit in the truck w/foot on brake etc.

Then, take a hose (3' of 1" rad hose works well) and try to isolate the location of the vibration/noise using the hose as a stethescope. Listen both inside and outside the cab of the truck.

Otherwise, I would think that a vibration without noise indicates that something is out of balance but I would also expect it to get worse with RPM and/or speed.

NothinButBowTies · January 30, 2004

Is it a constant RPM independant type of vibration that does not speed up w/RPMs?

It is at idle and only idle. The vibration cannot be heard, it can only be felt. With that said, would visual confirmation be the only way to figure it out?

booster · January 31, 2004

This is the only TSB that I could find that could pertain to your truck. There were a lot of other TSB's that dealt with rattles and noises at idle but this the only one that included vibrations.

Info - Buzz Noise or Vibration Felt in Floor or Throttle Pedal at Approximately 16 km/h (10 mph) or During 1-2 Upshift #03-07-30-032 - (07/22/2003)

Buzz Noise or Vibration Felt in Floor or Throttle Pedal at Approximately 16 km/h (10 mph) or During 1-2 Upshift

2003-2004 Chevrolet Silverado

2003-2004 GMC Sierra

Some customers may notice a buzz noise or feel a vibration in the floor or throttle pedal at speeds of approximately 16 km/h (10 mph). It may also be noticed during a 1-2 upshift.

This buzz or vibration may be a result of the supplemental brake assist (SBA) diagnostic test. (The SBA is mounted on the brake vacuum booster and creates vacuum for the brake booster in case of a vacuum loss or low vacuum to the brake booster.) The test occurs at 16 km/h (10 mph) after initial engine start-up. Normally, the test will not run again until the next engine start-up. Customers may believe that this is a transmission related noise as the 16 km/h (10 mph) diagnostic test may be very close to the 1-2 upshift speed under certain driving conditions.

This is a normal condition and no repair attempts should be made.

NothinButBowTies · February 1, 2004

Thanks Booster,

I am going to take it to the stealer next week and have the service advisor feel the vibration. Hopefully he can back me up when the tech says he cant find anything wrong.