New Z owner! I'm having major shaking in mid/rear.

[mikeyalphonse]

Hey guys this is my first car. I'm not too familiar with my 90' 300zx but I feel I know a couple basics. And will be around this forum for a while to learn and get even more familiar with Zs!
Now to the point:
My Z has given me little to no issues although lately i've experienced some major shaking around the middle and rear of the car when i drive and low speeds (5-15 MPH). But when i'm idle or going a bit faster i feel nothing. It's a very scary shake i've heard can be many things including bent wheels, drive shaft, carrier bearing, etc. Help for my first car/repair would be amazing! Thanks!

[Phan]

more description dude. it can be anything, maybe post a video so we can hear the nose.

[mikeyalphonse]

It's just a hard shake coming from underneath the car whenever i accelerate. It doesn't seem like anything with the engine because i feel everything right under me. I'll get a video soon if this doesn't help.

[Phan]

well that's a big clue right there. Sounds like your carrier bearing is blown. Stop driving that car till you can get it fix.

[mikeyalphonse]

i went to a friend's mechanic and he suggests that i might need a drive shaft balancing. could that be the problem or does the carrier bearing sound more likely?

[itsa300zx]

Get under the car safely and grab the drive shaft then try to shake it. Let's rule that out first, before trying to guess what it is on the internet.

[nissanfreak12]

Carrier bearing or U-joint. Carrier bearing will make it a harder vibration pretty much as long as the car is moving with thumping noise that may accompany it. Ujoints normally start vibration between 40-60 and sometimes settle after 60.

I will agree if you safely get under the car, grab the shaft and try and move it up ad down. If it moves, see whats moving, will more than likely be the carrier bearing.

U-joints are a little more difficult to diagnose, but factory u-joints cannot be replaced. Best bet is to get a one piece shaft and be done with the center carrier bearing. The u-joints are also replaceable. Not much more expensive than the carrier bearing.

[mikeyalphonse]

Cool thanks guys i will check drive shaft first thing tomorrow morning and get back to you.

[mikeyalphonse]

Update: I was able to get to the drive shaft and it wouldn't budge in any direction, even with slight force. What else could the problem be now that that's out?

[nissanfreak12]

Do you feel it in the seat? If so, swap the rear tires tire to the front and vice versa. If the problem still in the seat, you ruled out tires and wheels. Also when you have the rear end in the air, grab the wheel at 12 and 6 oclock position, try and move the wheel. If you have any play, bad wheel bearing.

If the problem is now in the steering wheel, issue with either tire or wheel. Take it to a shop and have them balance the tire. They may even see if the wheel has a bend or something.

How is the transmission mount?

[mikeyalphonse]

UPDATE: My mechanic assured me that it the shaking isn't the tires. And I checking my self to see that the drive shaft would move if I shook it but it did nothing. Although the vibrating feels be coming from around the drive shaft. I'm thinking I need a drive shaft balancing, a new carrier bearing, or I have a bad U-joint. Help please not sure what it is, still a bit ambiguous. These are just things I've been told.