"Honk" sound when stepping on the gas?

[olliec420]

Im surprised I haven't found any other posts about this when searching. I had a 97 Tahoe 4x4 in 2001 with 80k on it and when I hit the gas hard from a stop, it sounded like a honk from the back of the truck. Others heard it and would mention it, but I didnt think much of it. Figured it could be something with the leaf springs or shocks or bushing gone or something like that. Now I have a 98 Yukon 4x4 and it does the same thing. Certainly someone else has had the same. Im curious as to what it is.

 

[BlaineBug]

Maybe something vacuum related such as a vacuum leak or failing brake booster? Also possible for idle air controller to make strange noises when they fail, and seeing that your car is of the era that idle air controllers were used, that would be a place to look as well.

 

[tom3]

My best guess would be the (anti) sway bar bushing. Engine torque and the twist from it would make the back end squat on one side and twist that bar pretty good. Have a couple guys rock it back and forth and listen for the sound.

 

[B-train]

Or the slip yoke making noise. You could pull the rear drive shaft and see how it feels on the splines. Throw a little grease on the splines after inspection and test run.

 

[Hoesgottaeat2]

Of the (4) GMT400 styles I have owned, (3) of them have done this very same thing. Never completely nailed it down to exactly what it is. But I have strongly suspected it to be rear suspension related i.e. sway bar bushings, shock bushings or even leaf spring pads. Only does it from a dead stop. If I accelerate slowly to about 10mph from a dead stop it will not make the noise. And never makes the noise anytime besides accelerating from a dead stop. My '99 Hoe I own now has been the biggest culprit of this symptom of all I have owned. I don't see it as a critical issue personally. In almost 600k combined miles between the (4) of them, nothing has ever failed related to that noise. Opinion based on experience only.

In fact, the service history on my '99 from the previous owner seems to indicate he had GM service try to locate the root cause of the sound several times with no findings or resolve.

 

[OR VietVet]

I suspect that instead of a "honk" noise, it is more like a "squawk" noise, that I do have to agree, seems to be common because of the rear suspension and slip yoke set up. I have heard it and seen the complaints in the shops I was in. Unless it was an obvious part gone bad or bushings wore out, liberal amounts of lube(s) seemed to take care of it.

 

[east302]

Of the (4) GMT400 styles I have owned, (3) of them have done this very same thing. Never completely nailed it down to exactly what it is. But I have strongly suspected it to be rear suspension related i.e. sway bar bushings, shock bushings or even leaf spring pads. Only does it from a dead stop. If I accelerate slowly to about 10mph from a dead stop it will not make the noise. And never makes the noise anytime besides accelerating from a dead stop. My '99 Hoe I own now has been the biggest culprit of this symptom of all I have owned. I don't see it as a critical issue personally. In almost 600k combined miles between the (4) of them, nothing has ever failed related to that noise. Opinion based on experience only.

In fact, the service history on my '99 from the previous owner seems to indicate he had GM service try to locate the root cause of the sound several times with no findings or resolve.

Wonder if it’s something specific to a four door SUV (the rear sway bar)? I’ve not experienced that issue on three trucks (C and K1500) or my two-door Tahoe. None have the rear stabilizer bar.

Also, there should be some plastic insulators on the ends of the leaf springs - perhaps they’re deteriorating.

Edit: these things, a little plastic disc with a post. GM part 20870046.

 

[Hoesgottaeat2]

Wonder if it’s something specific to a four door SUV (the rear sway bar)? I’ve not experienced that issue on three trucks (C and K1500) or my two-door Tahoe. None have the rear stabilizer bar.

Also, there should be some plastic insulators on the ends of the leaf springs - perhaps they’re deteriorating.

Edit: these things, a little plastic disc with a post. GM part 20870046.

View attachment 387567

You may be spot on with that suspicion. As I mentioned previously, I too suspect sway bar bushings, shock bushings or even leaf spring pads(as you posted above). Nothing that worries me personally. Appreciate the differentiation you explained between the truck and SUV. That may help narrow it down at some point for me if I ever go looking for it again.

 

[olliec420]

I thought it might have something to do with the leaf springs myself. I may throw a gopro under there one day soon and see if I can make out where its coming from. Will keep ya posted.

 

[B-train]

I remember hearing about the leaf spring isolator issue. I had noisy springs on my 2015 3500HD and it was a squaking type noise due to dry springs and midwest road crap buildup. I sprayed down the springs with penetrating oil and they were quiet and smoother. It would be worth a try for yourself