Juicyblunts

Okay, so to start this off I am going to do my best to describe the problem I am having, as well as the corrective actions I have taken up to this point, with obviously no success. The car belongs to my wife, she purchased it used, and with several issues. When she got it, there was a smaller size tire on the front passenger side, the steel wheel on which the tire was mounted was severely bent along the bead rim, along nearly the entire circumference (curb mashed). This obviously caused several other problems with the front end, as it was driven in this state for an unknown amount of time, though clearly long enough to cause or at least worsen several problems. The wheel bearings were audibly in a state of crisis, the vehicle shook violently when decelerating from Hwy speed, and it was noticeably in dire need of new brakes.

I have since changed all 4 tires with the correct size, replaced 2 steel wheels, both front hub assemblies, all 4 rotors and pads for each (yes they have been broken in correctly), and the outer tie rod ends. As this was sufficient in correcting the obnoxious squeal of the front bearings, braking power & distance as well as the skull rattling vibration when decelerating, and some major improvement in noticeable vibration at low speeds, there is still a very strange noise in the front end which oscillates (intensity increases and decreases alternately) at around 110km/h or 70-ish Mph and above.

The noise arises with an accompanying vibration in the steering wheel and floor board, though not very noticeable in the seat or center column, which also oscillates in frequency and intensity increases when accelerating. The vibration and noise do not seem to correlate with a turning component, as it is not directly synchronized with the rate at which a turning component would be revolving (such as the wheels or propeller shaft), which lead me to replace the outer tie rod ends in hopes that what I was experiencing on the Hwy was merely the fighting forces imposed on the wheels by the road and the steering components. I have inspected the CV joints which show no signs of noticeable play, nor do the boots show any sign of tearing or expulsion of grease. There is only a minor popping sound when turning, with the wheel fully cranked, which sounds more like a ball joint than the characteristic "clunking" of a CV joint.

I am nearly at my wit's end with this issue, which is why I have come online to this and other forums to see what the collective knowledge of the Chev community can offer me in order to get this resolved. The car is booked for a wheel alignment for the last day of this month, though I have a cringing suspicion that this will do little-to-no good for correcting the problem I have described here. Aside from this, and some minor transmission work in the near future (typical solenoid issue with the 4T65E), the car is in pretty decent running order, however my wife intends to use the vehicle to transport our two young girls, which I don't feel is safe with the strange vibration and noise on the Hwy. Also, as for anyone wondering what exactly the sound I am talking about "sounds" like, it is almost like what you'd hear driving over rumble strips, though not as loud or violent. That is the best description I can apply to it, as it does not sound like a wheel bearing (hub assemblies just replaced remember), or metal-metal friction of any kind really, it is more like a tire noise, but not, if that makes any sense. Anyways, any and all help is greatly appreciated and I apologize for the novel but I wanted to avoid replying to things like "wheel bearing" or "warped rotor", etc. (Could be a warped rotor even thought they were just replaced, but I did run my digital caliper around each of them upon further inspection into this mysterious noise/ vibration, and they are bang-on all around the outer circumference.

U.Nanimous

Wow that's a long post...no time to read it all right now. I did skim through it looking for some information that is usually helpful to know though and I didn't see it. This forum is for the "Impala" and being that simple is actually a bad thing because problems on a '66 won't necessarily have the same solution as they would on a '16. So what year is yours? Also sometimes helpful depending on the problem (like I said I don't know yours for sure because of the length of your post) would be miles and recent maintenance.

Juicyblunts

Okay.. 2004 Base Impala 3.4L, 155,000 Km on it currently (just under 100,000 Miles).
Recent maintenance:
1. Engine & Cabin Air filters replaced & Engine Oil & Filter change #1 @ 153,874 KM (when purchased)
2. Engine Oil and Filter change #2 @ 154, 282 KM (original oil was BLACK and below fill line on dip stick)
3. Two new steel wheels and 4 new tires changed & balanced @ 154,350 KM
4. Brake rotors & pads, AND both front hub assemblies replaced @ 154,954 KM
5. Both outer tie rod ends replaced @ 155,120 KM

I have a wheel alignment booked for one week from today, and when the parts arrive, I will be replacing the Pressure Control Solenoid, Torque Converter Control solenoid, and Shift solenoids, as well as installing a shift kit and replacing the Transmission filter. The problem I am having does not seem to be transmission/ final drive related, and I am hoping that the wheel alignment corrects the "wobble" at around 70Km/h, but nothing has so far corrected the noise and accompanying vibration that oscillates at around 110Km/h and up. It sounds and feels as if I am driving on and off of the shoulder rumble strips when I reach these speeds, and is most prominent when I am accelerating/ applying throttle. It is felt mainly in the steering wheel and floor board, and I can press my hand firmly into my seat and center column and the vibration is not noticeable in either. Both front propeller shafts have been inspected and seem fine/ free of wear or play (surprisingly), so I am not sure what the issue is, unless one of the newly installed rotors are warped in/ near the center (I checked the outer circumference with a digital caliper). Axle spindle nuts and wheel lugs are torqued to spec and have been checked several times, leaving me with basically NO IDEA what is causing this noise and vibration.

U.Nanimous

Shorter version is definitely easier to read...
Looks like you got the major culprits taken care of already, it sounds like something that needs a passenger with their ear out the window.
What's your RPM's at when it starts? If you go to a lower gear can you hold those RPM's at a slower speed to see if it still does it?

Juicyblunts

The problem ONLY occurs when I reach 110 km/h and up. I could lick pavement all day in whichever gear I choose, but the problem noise is not noticeable until I reach those speeds. As for the RPM range, the car does not have a tach, but according to my OBD2 tool live data, the RPM can be as low as 1K while coasting from 120, to beyond 3K while accelerating from 110. The only noticeable relationship between RPM and the noise/vibration is the rate at which they occur/ how long each intermittent occurrence lasts. So the higher the RPM, the shorter the duration, but the greater number of occurrences per minute, whereas the lower the RPM, the longer the duration and therefore fewer occurrences per minute (hope that makes sense). This is all I can really gather beyond what I have already described.