odd noise from dash when back wheels spin free.

[Scottydoggs]

hi all, hoping someone has heard this sound before. i just got this 05 tahoe a few days back, it just snowed here so i went out to "play" and test things out, rpo's say its got a locker mainly wanted to make sure it works.

so if im moving, or from a stop if i spin the tires i hear this zipping sound from what seems like the behind the dash.

im thinking of jacking the back wheels in the air then putting it in gear to see if o can make it happen like that to pin point the sound better.

heres a vid of this noise cause its nothing ive ever heard before. truck has no dummy lights on at all. tc button works.

oh, t/c, this is with t/c off. but if it's left on it still makes the same sounds and does spin the tires.

it does it the first time, not the second, and then does it real loud the third time. other then this i see no other possible issues.

thanks scott.

 

[TwiztidPixel]

You have an exhaust leak somewhere. Manifold, flex pipe or gasket.

 

[PG01]

Is your dog in there with you? Sounds like a dog throwing up...

 

[1_8TTony]

Ruptured brake booster diaphram??????

Just a guess.

 

[Doubeleive]

pull the dash trim off and the bottom cover and if necessary the cluster and keep doing it till you pin point it, after listening to it sounds like it could be brake related, are you getting any pulsing/pulsating out of the brake pedal when it happens?

 

[Scottydoggs]

it does feel odd when i hit the brake to stop the wheels when i had it on a jack to repeat it.

i just bought the truck a few weeks back, after its first hwy drive coming off the hwy it started to pulse the brakes, feels like warped rotors or maybe lot rot on the rotors.

booster would be worth looking into, only i have hydro boost brakes.

ordered new brakes all around, R1 e lines and they are finally getting installed tomorrow. had em for days now. but work was in the way as always. hope that smooths them out.

made another post in engine section, has a second vid on a jack. http://www.tahoeyukonforum.com/threads/odd-sounds-behind-dash.99204/

 

[Doubeleive]

is the abs light on? even if is not any pulsating feeling could also (possibly) be from the abs system which runs off of a main unit that gets information from the wheel hubs, if there is bad hub or bad wheel sensor it can cause a pulsing but it is usually pretty apparent when coming to a normal full stop at the very end of the stop you would get a pulse and/or jerky stop and the abs light would normally be on or would come on then go back off again when you shut off and restarted. you can check the front wheel hubs for play by simply jacking it up and seeing if there is any play when you try to move the wheel 6-to-12, a little play at 3-to-9 is normal as the wheels will move with steering, a lot of play at 3-to-9 would be tie rods or linkages, but 6-to-12 should have no play.

 

[Scottydoggs]

not a single dummy light is on. stops smooth until the brakes get some heat in them. then they pulse, goes away when you let off the brakes of course.

its definitely not abs pulse as far as i can tell. i know what that feels like.

ill check the hubs for play when i do the brakes. ive warped rotors before, it feels just like that.

i can also hit the local garage here, guy has let me use his snap on scanner for free in the past for abs codes on my regal. be worth a look for whats in history.

main issue is wtf is the damn zipping sound when they spin free. never heard that one before.

it kinda reminds me of a abs sound when its active and your braking hard in snow with the pedal hitting the floor like a mush pile.

 

[Doubeleive]

ya that's what it kind of sounds like

 

[Matahoe]

Noise could be the auxiliary brake booster pump engaging. I know it makes noise at low rpm when there is a traction control event that limits wheel rotation so you don't fishtail all over the place. I tried to do the exact wheel spin on an icy driveway yesterday and I got pretty much the same effect as you did.