My Z is roaring

[300zxman1987]

Hey guys,

I have a 93 300zx 2+2 5spd car

I've recently had a problem that I can't figure out. It all started with a roaring noise a few months ago and one day I was pulling into work and my shifter plate broke. I had no idea what happened at first until I took the center consol apart and seen that the rubber that held my short throw off the drive shaft had broken. So I ordered a new one and installed it but I still have this roaring noise that I can't figure out. The first thing I did when I got the car 3 years ago was replace the rear end and transmission oils with the proper weight mobil 1 syn oils. Today I took the car to the lube shop and got them to check the level in the transmission for fear that the oil I replaced had leaked out and it was running dry and causing the roar noise. But it was full so I don't want to think its the trans, my car has the 5th gear grind but only when going from 4-5th at above 4-5k rpms. The joints between the transmission and driveshaft and the joint in the 2 piece drive shaft could they cause a noise to sound like it's coming from right below the shifter? The noise is noticably worse in 1-2rd gear you can't really hear it at highway speed and worse when you let out the gas and the car is slowing down using engine braking.
It's got 161k on it and any advice you guys can give me will help. What parts to buy and things to try.

[fabbio25]

Had the same problem with my car. Changed the driveshaft to a Z1 onepiece and installed nismo transmission mount and the problem was solved.

[300zxman1987]

Did the noise quit when you pulled in the clutch or put the car in neutral?

[fabbio25]

It was not constant and only happened when going through the gears in the upper rpm ranges.

[300zxman1987]

So I'm right by thinking that if it's in the driveshaft that when you push the clutch in the shaft quits spinning therefor the noise stops?

[Ace2cool]

Most likely the driveshaft carrier bearing. Upgrade to one piece and problem will most likely be solved. Shaftmasters is a sponsor on here, and if you talk to David and tell him Aaron from NICOclub sent you, I'm sure he can hook you up with a NICO member discount.

[Ace2cool]

Also, this should be in tech, for future reference. I'll move it there now.