Drive Train Axles Bearings problem
2007 Infiniti G35 6 cyl All Wheel Drive Automatic 42000 miles
HI, I just recently bought new set of michelins pilot sport a/s plus for my 2007 G35x sedan with OEM wheels/rims. A week after this, I installed new sport rotors from EBC (3GD Sport) and brake pads from Bendix (ceramic CT3).
My problem is that the steering wheel was vibrating at 60-75ph. I had the tires and wheels road forced balanced 3 times but the vibration is still there. So I went ahead and checked all brake parts and suspension parts for looseness and play. No there was no play in either those parts nor the hub bearings. So I put the wheels back on, this time putting them on very flush against the rotors hub, tightened the lugs by hand before lowering the car and torqing the lugnuts to 80 ft/lb.
This remounting of the wheels helped a little bit. The shimmying was very small and not too noticeable now. I think the wheels were not mounted fully flush against the hub/rotors.
Ok so, another week after this, I'm experiencing an excessive road feel in the steering wheel and shift knob (very high frequency vibration?) At city driving speeds. Also even on the floor boards, I can feel vibrations with my left foot. These vibrations can be felt accelerating from 0mph - any speed. As I push the gas pedal to accelerate, I can feel this " excessive road" /high frequency vibration in the pedal traveling through the steering wheel and the shift knob and a little bit in the seat.
Could this be an engine mount? Or a worn bushing? Or stuck caliper maybe (the brakes are very smooth by the way, no pulsations or feedback from the brake pedal)?
Please help. This is getting to be very annoying. I cannot drive for more than 5 mins without my hands becoming numb.
Also, I would like to add that I had the car 4-wheel aligned also at a " town Fair tire" store. They are the ones who I purchased the tires from. They also did the installation. They aligned my car twice. The second time to correct the steering wheel pulling to the right. So now, my car seems to have perfect and straight steering wheel. But this high frequency vibration is killing me. I used to love driving my car. Now I hate it. Even though the alignment seems good (from the perspective of the steering wheel), could it still be that?
June, 9, 2010 AT 6:43 PM
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.
June, 10, 2010 AT 7:50 AM
Thanks for the reply. I'm not sure if its the bearings though. I wiggled the tire and wheel when the front end was raised to see if there was any play. Everything is tight. No movements. I did it with a good amount of force also. Still no movement.
I've never heard of a stethoscope being used on something like this, but I guess it is feasible.
I wouldn't have a clue of where to get one.
THere is no noise coming from anywhere that I can hear. I drove while having all windows down to see if I could hear anything. And nothing is to be heard everything is silent. Turned the wheel. Everything is silent.
The only feedback I get is the very fast, but slight, vibrations in the steering wheel and shift knob. And most of the time on the floor boards too. Its like I am receiving every single road feeling being transmitted through the steering wheel. You can't really see the steering wheel vibrate. But you can definitely feel it. It makes my hands numb after 5 mins of driving : (
There is no sound whatsoever. But then again, that might be only to my human ear.
June, 10, 2010 AT 4:31 PM
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.
June, 10, 2010 AT 6:05 PM
Thanks for the in-depth reply caradiodoc.
Alignment question: if the steering wheel is perfectly centered, is there still a chance that the car is misaliagned somehow? I know about toe, caster, and camber. But not much.
As for tire wear. It is only 2 months old. There has not been any signs of wear yet. I would think tire wear would cause higher amplitude vibrations than what I'm feeling. I could be wrong.
I can feel the engine vibrating in the steering wheel when the car is at a stand still. It is very slight. But it is there. Once I step on the gas, I can literally feel things spinning up transmitting even more vibration to the steering wheel as well as the shift knob. This vibration can be felt anywhere from 0mph - 75mph. It is as if a mount or a bushing is worn. Or maybe it could be the drive shaft?
It definitely feels like some sort of dampener or bushing is worn.
June, 10, 2010 AT 10:16 PM
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.
June, 11, 2010 AT 7:56 AM
I'm actually learning a lot hehe. Thanks caradiodoc.
Now that you mention it, I think I'm going to lean more towards a harmonic balance problem. How much do you think this will cost to fix? My car is still under basic warranty. Do you think they will cover this? Is it potentially a warranty item?
I am going to bring my car to the dealership next week for them to check it out. Hopefully it will be fixed under warranty. If not, I hope the price isn't too high.
June, 11, 2010 AT 10:39 AM
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.
June, 11, 2010 AT 10:58 AM
Yeah, I will see what they have to say. I will keep your words in mind when approaching the dealership.
Thanks again for your expertise and input into this issue.
I will report back what they find after the visit next wednesday.
June, 18, 2010 AT 2:57 PM
Welp, just to update, I went to the dealership, and they could not find a darn thing wrong with my car. Go figure : /
THey said my car was the best/tightest/cleanest '07 sedan they've seen come into their garage.
The driveline humming vibrations are still there. But I guess it is common in these infinitis. I had a 2009 G37x sedan for a loaner and it drives the same way as my car, if not, rougher. It had the same humming vibrations which can be felt in the same areas (steeing wheel, floor, and shift knob).
The techs said in all his time in being a Nissan/infiniti tech, he's never seen an engine mount or a transmount fail on these cars. So it couldn't be that.
Surprisingly, after the dealership visit, my car seems a little smoother also. I mean, transmission-wise, it doesn't shudder as hard anymore. It's not really noticeable now. I wonder if switching to the OEM air filters had something to do with this. (I had K& N air filters before, and I read that they sometimes mess up MAF sensors because of the oil on them). I also took off my grounding wires (waste of $100 by the way). The only thing Ground kit does is give more power to your windows and radio : / The gearshifting and gas pedal still feel the same, if not, smoother when I took the GK off. Which is weird. Maybe taking the Negative off the battery for more than 30 mins. Does this.
Braking is ultra smooth as opposed to 3 weeks ago where it would shudder if I press it hard. Maybe the rotors " unwarped" themselves? Lol.
I guess I can live with my car. Maybe buy some racing gloves to alleviate the numbing effect lol.