Hello all, once again asking help from my friends across the pond.

Living in the Netherlands, Europe, its hard to find mechanics or people with experience on these cars. Ill cut right to the chase.

Have a 2008 Imported 370 GT, sport package 6MT, 4WS. Car is bone-stock apart from the CSC kit. Had a bad wheel bearing about 5 months back, fixed that, no problems. Now about a month ago the car started vibrating at about 80 kmh (about 50 mph) and keeps on doing it well until i reach the limiter at 190 kmh (say 120mph). Vibrations are felt slightly in the steering wheel, in a way that when i let it go at 60 mph, you can actually see it shaking a bit. Brake pedal is solid, no bumping there. Whole car seems to be shaking, you can feel it most through the seats and floorboards, at higher speeds its still there but harder to notice, same goes for lower speeds than 50mph. Its not so bad that I cant see through the mirrors or anything, but its getting more intense the more I drive the car.

So far I have done:
- Rotated wheels, checked to see if they were damaged/crooked
- Balanced wheels, got new tires up front, to no avail
- Swapped complete set of wheels for my spare set, to no avail
- Swapped brake rotors + pads in the front
- Had all rotors checked for play/ misalignment
- Checked tie rods for play, replaced outer ones just to be sure

- I have a miniscule amount of play on the ball joint on the lower control arm, ordered new arms but I find it hard to believe the whole care is shaking in the floorboards because of that. I am suspecting the driveshaft myself but have read stories about diff bushings, guibos, carrier bushings, all the muck. Wondering where I need to start looking?

Any form of help and/or advice is greatly appreciated! Thank you all in advance.

Kind regards,

BB

 

Ah yess the unfound able vibrations.

You should put the car in the air and run through the gears while in the air. This can let you know if your drive shaft or carrier bearings are messed up and causing secondary vibrations.

Your primary vibrations being that you checked all of this are Wheel bearings. Wheel bearings on these cars dont usually crap out as many others where they would be making noise which would be a dead giveaway.
You should pay attention as you let go of the wheel and notice the vibrations, slightly move the wheel by the bottom just increments. What this will cause will be to show it's play.

I have balanced, adjusted the whole front thinking a slight bent wheel was my issue although it balanced correctly the problem was still there.
It wasnt until I was reversing that when I would press on the brakes I would hear my break pads hitting the rotor. This meant that the pads had retracted fully ( not common on it's own) This lead me to think something was pushing the pads back into the calipers and the only thing that can do that is play in the hub from the wheel bearing. This along with the vibrations I never got to solve convince me to believe that I have wheel bearing issues.

 

Perhaps your driveshaft is unbalanced. Not a common problem, but a real one nonetheless.

 

DS would be secondary. Being that he's complaining about steering shake and has taken the proper measures to determine the possible rotary components are balanced. The last ones to check are wheel bearings.
Like I said usually they make a loud noise prior to but not so much on Infiniti/Nissan. Sadly this is due wide wheels or spacers with a decent overall offset.

 

Thanks for your reply Bull and Rochester.

I went through first gear with rear wheels in the air yesterday, need to do the rest of the gears still since i only did it to look at the center bearing. Bearing seems to be fine and doesnt seem to be allowing movement. Guibo looks fine as well.

(Not so) Fun thing is that when I replaced the wheel bearings, my torque wrench broke so I am quite sure they (and with that the wheels too) were tightened with too many uggaduggas. Car has done 150k kms, roughly 90k in miles. I also noticed a weird pattern on the front rotors on both sides, Ill add some pics here. Please remember I swapped out rotors and pads at the same time so there was nothing caught in between them or any weird wear to them prior. Replaced the wheel bearings first, shaking occured, replaced rotors and pads after, since then it has been about a month.
As far as wheels etc go, im running the stock sport package 19" Enkeis, no spacers or anything else done to the suspension apart from the tie rod replacement, which was an OEM part.

Perhaps the installation with the torque wrench messed up the wheel bearings a bunch. I would rather fix that of course. I can however get a whole axle from a donor car for 150 Euros (160 dollars) with 40k miles on it if I need to.