Groaning Noise from Dash while accelerating

[whip]

I have an issue that is leaving me stumped.

While in 2-HI, when I start out from a dead stop, at about 5-10 mph I hear a "groaning noise" under the dash on the left side. It is subtle but definitely there. At the same time I see a slight dip in the voltmeter and if the headlights are on the lights will flicker once. It does it almost every time I start moving forward from a dead stop.

I do not get any "traction control active" messages on the dash but I thought it was the traction control kicking in.

I tested that theory by disabling the traction control and the noise, voltage drop, and headlight flicker all go away.

I also checked 4WD and if I have the vehicle in Auto 4WD or in 4-HI it does not happen at all.

I have cleaned the front wheel speed sensors and that did not make it go away. I am planning on cleaning the rears next to see if that helps.

Has anybody ever experienced this and if so, what was the fix??

Thanks.......

 

[Tz1G]

I get that slight noise when accelerating to 5-10 mph. It's not enough to be worrisome to me. But if it gets any worse, I would take notice. It almost seems like a tranny noise on mine. (03 z71)

 

[whip]

I finally got the Tahoe on speed scanner and it turns out I had a faulty left front wheel speed sensor. Replaced the sensor and all of the issues are gone.