2007 Infiniti G35 steering wheel and shift knob high freque

Hi pianofrk4. Welcome to the forum. This sounds typical of noisy wheel bearings. Actually, it sounds a little extreme but you've already covered the other likely causes related to suspension and steering parts. Noisy wheel bearings will make a buzzing sound similar to an airplane engine. That is real common. They can get bad enough to cause a vibration that you can feel but that is not real common.

The easiest way to find a noisy bearing is to run the car in gear on a hoist and listen next to each one with a stethoscope. The grinding noise will be very evident. Another, more involved method is to use a tool called a "chassis ear". That is a set of six microphones that you clip to various suspect points, and you run their wires inside the car to a receiver box. You listen with headphones while driving the car and switching between te microphones. By moving the mics around, you can zero in on the cause of the noise. Be warned; a lot of mechanics have never heard of this tool or seen one, but they are used in most new car dealership repair departments.

Caradiodoc

You can find the stethoscopes at any auto parts store for around ten bucks, but wheel bearings aren't the problem if you're not hearing the noise. They will be tight yet when they're noisy; looseness has nothing to do with the buzzing noise they cause.

Next, look at and feel the front tire wear. A toe problem will cause a featheredge pattern that can cause a vibration when drving, not when standing still. Rub your fingertips lightly side to side on the tread and around the tire in both directions, particularly on the sides of the tread next to the sidewalls. You should feel the same thing in both directions. If you feel a smooth transition from one block of tread to the next in one direction, but a raised sharp edge in the other direction, the toe is misadjusted and causing a wear pattern that will cause a vibration. Both tires on the same axle will show the same pattern. This wear would have been noticed by the alignment technician or by the person who removed the old tires. Since the car was recently aligned, this type of tire wear so early would suggest the equipment slipped on the wheel after it was calibrated or the computer was out of calibration. While either of these are possible, I suspect the vibration is not alignment-related.

Vibrations can also be transmitted from the engine to the passenger compartment by an engine mount that is broken or off-center so it allows the metal parts of the brackets to touch. They are supposed to be isolated by rubber inserts. Exhaust hangers can do the same thing if the metal parts come in contact with each other. Mounts and hangers can transmit vibration when the car is standing still, but they usually don't cause this problem all the time. Cornering or driving over bumpy roads will give those parts the chance to shift position once in a while causing the vibration to stop momentarily. The exception would be an engine mount with a deteriorated rubber insert that is allowing the weight of the engine to hold the metal brackets in constant contact with each other.

Another thing to try is running the vehicle in gear while its jacked up or on a hoist to see if you can duplicate the problem. The plan of attack would be to use a pry bar to move things around while the vibration is occurring to see what affects it or makes it go away. You also must try to determine if something is causing an abnormal vibration or if it is a normal vibration that isn't being properly isolated. Abnormal vibrations require something to be fixed or replaced. Normal vibrations that aren't being isolated require finding the path the vibration is taking and correcting that path.

Chrysler had a special tool many years ago that saw very little use, but it was designed to identify the cause of vibrations. It was connected to their scanner and compared the frequency of the vibration to the speed of the car. It would identify a tire balance problem by the frequency being the same as tire rotational speed. A universal joint on a rear drive shaft vibrated at around three times tire speed. Wheel bearings and tire wear vibrations were much higher in frequency. Even bearings supporting shafts in transmissions and transfer cases could be identified by their frequency and under which operating conditions they occurred. I don't know if that tool is still around. It got such little use because the cause of most vibrations were found before that tool was needed.

Caradiodoc

If the toe is off on either tire, there will be the wear I described on both tires. Toe wear is always a result of total toe of the two tires, not individual toe on one tire. If toe is off on only one of them, the steering wheel will be off-center when driving straight ahead. Toe can be off equally on both tires in which case the steering wheel will still be straight. Normally misadjusted toe will not cause a pull when you let go of the steeing wheel, but if the two front tires are steering in different directions, the car has to follow one of them. That will be the tire with the most weight on it, and that is usually the right one because roads tilt to the right so rain will run off.

We can narrow this down to something not related to the alignment, tire wear, drive shafts, or even the transmission because the vibration occurs when the car is not moving. That should make it a lot easier to find. Some additional things to look at include the vibration damper on the front of the engine and the possibility of a balance shaft that isn't doing its job.

The harmonic balancer / vibration damper has a heavy metal ring separated from its hub by a thin layer of rubber. Its job is to dampen the twisting action of the crankshaft caused by the pulses of each piston as they apply pressure. Ford has had a lot of problems with that rubber breaking loose and allowing the outer ring to spin on the hub. Some engines are "externally balanced" meaning they couldn't cast all of the counterweights on the crankshaft so one is cast into that outer ring and one is cast into or added onto the flywheel, flexplate, or torque converter. If that ring spins on one of those with the added weight, it will cause a miserable vibration but it usually won't be felt at idle. A clue can be found by shifting to neutral and letting the engine idle while coasting from highway speeds. The vibration will become more severe the faster the engine is going.

The same is true of engines that use a balance shaft except problems with these can usually be felt at idle. These shafts spin in the opposite direction of normal crankshaft rotation and at twice engine speed. They were mostly used on four cylinder engines which naturally vibrate more due to fewer power pulses per crankshaft revolution. Some six cylinder engines use them too. The Chrysler 2.2L, for example, feels like any normal four cylinder engine, but the nearly identical but newer 2.5L uses a balance shaft and runs much smoother. Their balance shaft is run off the timing belt. Some engines use a separate chain to drive their balance shafts. On almost all engines, if the sprocket is mis-timed by just a few teeth, there will be a noticeable abnormal vibration. When it's just a little out of time, the shaft doesn't cancel out the normal engine vibration, but as it gets closer to 180 degrees out of time, its designed-in vibration adds to the engine vibration making it even worse than having no balance shaft at all.

The question is, if the balance shaft is indeed causing the problem, how did it get out of time? It is free to spin and presents very little load on the belt or chain so it rarely gets out of time on its own. Most commonly the problem starts after someone had it apart to replace components.

Since you can feel the vibration when standing still, have a helper pry on the engine to lift, turn, twist, or shove, ... Anything that will repostion something while you watch for a change. You might consider removing the serpentine drive belt from the power steering pump and generator, then running the engine long enough to see if the vibration changes.

Caradiodoc

Can't help you with that, but a harmonic balancer would be engine-related, and the engine is part of the drivetrain which often has the longest warranty. First wait to see what they find. If it is indeed the harmonic balancer and for some reason they will not repair it under warranty, just smile and tell them you'll drive it that way until the crankshaft breaks, then they will have a major repair that WILL be covered under warranty. You might also mention that you'll be sure to point out the vibration to all of your passengers. That's my sarcastic answer. I suspect in reality they will not argue about the warranty. What might be at issue is if there is a deductible that you'll have to pay. I have no idea on the cost of a new balancer, but I do know that the auto parts stores have catalogs full of replacements for almost every brand of car so there must be a lot of trouble with them. They don't stock parts that never fail. I actually just replaced mine on my very high mileage '88 Grand Caravan, but it was my own fault. The bolt worked loose and it wobbled off and got chewed up. My replacement came from the salvage yard for five bucks. It only took ten minutes to replace it. Some cars will take longer if it's hard to get to.

Caradiodoc

Hmm. Well, those vibrations might indeed be "the nature of the beast", and it's interesting another car did the same thing, but I think the engineers would have noticed that and dveloped a fix for it. Please holler back if you find a cure or more information. There might be a service bulletin too for this issue. A bulletin is not a recall. It is a note to the mechanics who might be scratching their heads over the same hard-to-diagnose problem. They are intended to save them the time and grief of trying to find what other people have already figured out.

As an example, I had a Chrysler minivan about 12 years ago with a shudder in the steering wheel, but only at 33 - 34 mph; no other speed. Didn't find any service bulletins. Called Chrysler Tech Assistance after about six fruitless hours of searching for the cause. Come to find out, stupid me entered the most common engine size in the computer during the search of bulletins because what difference should engine size make. Ends up there was a bulletin for my exact problem. I would have found it if I had entered the correct engine size as it only affected vans with that one engine. The fix was to simply replace a dampening counterweight with a lighter one. Ten minutes later the problem was solved.

I don't have access to bulletins now except what I stumble across on the internet. If I see something that might apply, I'll post it here.

Caradiodoc