Popping from front end? Tried everything..

[Wicked Mayhem]

If I floor my Tahoe from a stop the front end lift and pops. Then if I slam on my brakes hard enough it will pop again. What’s weirder about it is if I floor it and it pops, I can slow down normally with no pop, and floor it again and it won’t pop. I have to hit the brakes hard for it to pop. It has to pop up then it has to pop down. It won’t continue to pop when I floor it unless it pops when brakes. Sounds like it’s coming from the front passenger side. It did it with all the original front end parts, it was loose and I figure it was from that. I’ve since then rebuild the entire front end suspension/steering minus the steering box. It still pops like it has before I rebuilt the front end. I’ve loosened everything more then it should be, tightened everything more then it should be, and torqued it all to factory spec trying to find the smoking gun with no luck. I’ve lubed everything on the front end again with no luck. Suggestions? Something cracked? Body bushing? No clue. No rust on this thing.

 

[Carolina Brown]

When you say you 'rebuilt the front end', did you replace the Upper and Lower Control arms? The CV's? The keys? The torsion bars? The cross bar that the keys mount to?

Does your Tahoe have a lift?

 

[Wicked Mayhem]

Upper arms
Lower arms
Hubs
Shocks
Inner tie rods
Outer tie rods
Center link
Pitman arm
Idler arm

Didn’t replace keys or torsion bars. I had them out obviously when I rebuilt them and saw nothing wrong with them.

It’s 2wd. Lift spindle and hardly any crank on the torsion bars. Stock keys

 

[Fless]

What do the sway bar frame bushings and links look like?

 

[Wicked Mayhem]

What do the sway bar frame bushings and links look like?

Oops I replaced all of that too. Literally the only things old left on the steering or suspension is the steering box, torsion bars, keys, spindles and steering column. Unless I missed something again lol.

 

[exp500]

Loosen and retorque Control arms at ride height.

 

[Wicked Mayhem]

Loosen and retorque Control arms at ride height.

Did that from the start. everything was torqued once it was in the ground and moved around some. I’ve redone that a few times. Also tried loosening and tightening more then it should be to see if that helped with the same result

 

[swathdiver]

Go-Pro camera time.

 

[nonickatall]

It sound like some hard moving connection or some loose connection with two positions where a force is needed to make the plop. So it moves under the force of the acceleration and moves back under the force of brake.

It can come from the suspension where you changed everything, or from the powertrain, where is an enormous twistforce when you are accelerating.

So i first would check the motor and gearbox mounts. When your motor makes that plop on the force of accereration and at hard brake, because of the mass inertia back, then you can have this symptom.

And additionally a stupid idea to check..

Search for a place like a wooden bridge, where you can tie your front wheels with tie-down straps to the ground. Then lift your car with a carjack on the axle carrier to simulate the acceleration force on the suspension. Listen closely.

You can also use some wood to push with the carjack on your motor/gearbox and see if you have movement in some mounts.

Excuse my bad English i'm from Germany.

 

[MassHoe04]

In the US... Unless you own one on your property or have a friend with one, there are not that many wooden bridges to be found where you could just park on it, strap it down and mess with your truck for a while.

I could picture: Even if we could find a wooden bridge to strap the front end on, THAT would be the very moment someone would come along expecting to use the bridge and get all pissed off! That would be my luck, anyway.

Not laughing at you. Just the the idea of one of us trying to do this here in the US and how that might go.

Your idea is not bad at all. Maybe a trailer with tie-down anchors would be a good substitute for a wooden bridge.

 

[Alex_M]

I agree, check motor mounts, transmission mounts, etc. I'd even check rear end stuff. Sometimes sound travels in weird ways.

 

[nonickatall]

In the US... Unless you own one on your property or have a friend with one, there are not that many wooden bridges to be found where you could just park on it, strap it down and mess with your truck for a while.

I could picture: Even if we could find a wooden bridge to strap the front end on, THAT would be the very moment someone would come along expecting to use the bridge and get all pissed off! That would be my luck, anyway.

Not laughing at you. Just the the idea of one of us trying to do this here in the US and how that might go.

Your idea is not bad at all. Maybe a trailer with tie-down anchors would be a good substitute for a wooden bridge.

Then lay a wooden beam on the floor, drive with the the front wheels on it, an tie it down.

Not problems made your country great, solution did it ..

 

[Doubeleive]

there is a TSB that has been around for along time for the crossbar under the engine area, the fix for that one is to remove the bolts and swap them around and re-torque.
could also be a body mount
the snap/pop thing is just problematic for the gmt800's & gmt900's
sometimes the only fix is to lube the crap out of the sway bar bushings a couple times a year as that is the primary cause, that and a change in weather.

 

[SnowDrifter]

Adding to what's been posted, there's also a TSB about some body mounts. Might be worth looking at

http://ww2.justanswer.com/uploads/heavychevy396/2010-01-02_123934_Underbody_Pop_or_Clunk.pdf

 

[houstontaylor]

I got a set of Chassis Ears for my popping sounds. The signal on the rear upper shock bolts coincided with the sounds. Replaced the bolts in case they were worn but no change. Maybe the holes for them are enlarged.? Solution in progress.

 

[Trey Hardy]

My Tahoe makes somewhat of a similar sound I’ve narrowed mine down between the front differential mounts and or a passenger side Motor mount same deal everything up front is new but still does it from time to time

 

[Joeltz]

There is a service bulletin referring to re torquing a arms ( you have Done , and I think the Crossmember bolts get retirqued also

 

[Fless]

If it's 4wd, check the front differential mounts. The bushings by now are probably worn.

 

[Carolina Brown]

If I floor my Tahoe from a stop the front end lift and pops. Then if I slam on my brakes hard enough it will pop again. What’s weirder about it is if I floor it and it pops, I can slow down normally with no pop, and floor it again and it won’t pop. I have to hit the brakes hard for it to pop. It has to pop up then it has to pop down. It won’t continue to pop when I floor it unless it pops when brakes. Sounds like it’s coming from the front passenger side. It did it with all the original front end parts, it was loose and I figure it was from that. I’ve since then rebuild the entire front end suspension/steering minus the steering box. It still pops like it has before I rebuilt the front end. I’ve loosened everything more then it should be, tightened everything more then it should be, and torqued it all to factory spec trying to find the smoking gun with no luck. I’ve lubed everything on the front end again with no luck. Suggestions? Something cracked? Body bushing? No clue. No rust on this thing.

Here's another idea. If you have changed the CV's or knuckles and you reinstalled them, maybe you didn't torque the CV's properly?? If you torque the CV axles to knuckle while tires are off and truck is in the air then the CV is not compressed to it's proper length. The truck must be on the ground with full weight on front tires THEN you torque down the CV.

If it wasn't torqued properly then any time the front end goes up or down, the CV can slide laterally in the knuckle stopping when CV nut impacts knuckle...probably millimeters.

 

[Carolina Brown]

last thing...since you've checked everything else check the front wheel bearings. I know failure modes for wheel bearings are noises and vibrations but just check...you've checked everything else