Hello Again,

I had experianced something with my Blazer that I never had experianced before, It is 4x4 SLS full size model with a recently rebuilt tranny and tons of work.

After I took a 150 Mile trip to a small town nearby this weekend, I stopped vehicle in my driveway and let it idle for about 30 seconds while I was gathering belongings and began to notice a high pitched Moan/Whine.

I could not distinguish the exact area it was coming from, But it sounded like from the under-center of the vehicle.

Things I have recently done:

Installed new Stereo and Amp incl; Drilling holes for wires.
New shocks in the front
Toe adjustment in front
New rear end

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The noise seemed to come slowly at first and then gradually increased in volume until it was a constant humming whine, I shut the vehicle off and have not since heard it.

For the record, I have not switched from 2WD to 4WD in at least a couple months, So it couldnt be that since it has been in 2WD without any problems until yesterday.

Wondering if its my Vacuum system, the Tranny, or possibly something like the water pump dying.? If it disappears and I dont hear it again should I forget about it?

 

If it is while stationary at idle, then nothing that you have done would cause this aside from possibly putting a screw into a heat shield that over time causes the vibration of the engine to be amplified.

I would say it has something to do with the transmission.

If it does truly disappear, then do not sweat it.