This is weird.

I'm driving at cruising speeds, let's say 65mph. The car will vibrate seemingly from the transmission/rear area of the car. If I let off the gas, everything goes back to perfectly quiet and smooth. The vibration is not dependent on engine speed but vehicle speed. I can go to/from 4th or 5th gear and the vibration is the same pulse. The feeling is similar to being in too high of a gear and hitting the gas, you know that lugging-feeling vibration? It's so bad at 75mph that the whole console area near the shift boot will vibrate and make my cd player skip.


Other clues:
-When in reverse with the windows down, i can hear little clinks as I back up.
-The noise only appears when I have the accelerator pressed. Any speed, any gear during deceleration is perfectly quiet and smooth.


I'm guessing some sort of driveline bearing? What would only react to acceleration? I can automatically rule out balancing, alignment, etc.

Any help would be appreciated! I'm mobile again and looking forward to the next Cali meet, but my butt will be numb from the vibration by the time i get there!

 

the vibration noise/feeling that you are experiencing is more than likely a bad u-joint on either your driveshaft or rear suspension. My Z had the same problem, and it would only get worse at higher speeds, since the wheels are moving fast. If it is the u-joints, you will also hear a loud clunking noise when shifting unless you shift very smooth. I'd check those first, you can tell they are bad if you get under the car and the u-joint moves when you try to twist the driveshaft. It should move maybe a centimeter or two, but if it has alot of play, you know you have found your problem.

 

Awesome. Assuming I have found my problem, what am I looking at in terms of replacement? Big job? Do-it-myself?

I'm still poor from the injector project... is this something I can have welded?


Thanks for the input! I'll try to get out there tomorrow and check it out, in the interim, is it safe to drive with the vibration or am I looking at dropping a driveshaft on the freeway?

Thanks!!!!!!

 

Going with a lighter 1-piece steel drive shaft is an option. Fixes the problem and will free a couple of horses to the wheel. Z1 Motorsports has one at approx $240. Nyx Motorsports has one sale right now for $199.
I haven't done it myself yet but i doesn't look terribly difficult. Perhaps have to drop the exhaust to get to it.

 

oh, it's very easy to fix, u-joints are only a pain in the *** because you have to crawl under the car. They shouldn't be too expensive, for the driveshaft u-joint you should be looking for something under $20. You can buy them from Kragen's or AutoZone. To get the driveshaft U-joint out, you want to crawl under the car, and unbolt the driveshaft from the rear differential. You might want to get a bucket for when you pull the driveshaft out of the transmission, it might leak some gear oil. To get the u-joint out, just get something the size of the cap of the u-joint, and just pound on the u-joint until it comes out of the driveshaft, then replace them. It's kind of hard to explain in short words, but once you get a look at it, I'm sure you'll figure it out.

Oh, here's a u-joint.

 

it also depends on the severity of the situation as to if it will fall out. I've driven on a set of bad u-joints on the freeway, and you will know your limit when you feel like the car is going to shake itself to death. Mine was so bad that the u-joints practically fell apart when I dropped my driveshaft, but it's a very easy problem to fix. I just wouldn't push the car any more than you feel safe.

 

get a propane torch too. sometimes they wont want to come out but a little heat helps. also, i'm not sure about the z32, but some manufacturers use some lead epoxy something or other instead of retaining clips, and the heat will boil that out and make the job a hell of a lot easier.

 

and........ don't drive for very long with the bad u-joints. Those not-so-good-vibes will quickly kill your tranny output shaft bearings and your differential input shaft bearings. While your under there, go ahead and change your tranny and diff oil.

lol...... watch your legs when they're sticking out in the street. we wouldn't want them run over.

 

Don't waste your time changine the u-joint. Just get a 1-peice driveshaft and replace the whole thing. More than likely the driveshaft center bearing will be or is gone as well. Get a 1-peice and eliminate everything at the same time.

 

The Nissan dlrs will tell you that the u-joints cannot be replaced. BS!, they are staked in but a good driveline shop can change them over to the old style which were/are held to gether by the circlips.
That said I, like many others changed over to a one piece, works great.
IIRC, to remove the old one, unbolt it at the diff,remove the cat covers and upper aluminum heat shield. Undo the center brg and pull. If you are going to reuse the orig ds, remember which way the brg mount spacers go in.
Cheers

 

I ordered a one-piece from Nyx motorsports ($227 shipped w/ tax) this morning. I should have it in a couple days. Crossing fingers. I'll let y'all know what happens.

 

FIXED.

I got my 1pc. driveshaft in, and upon inspection of the old one, the u-joint was fractured. Wouldn't even bend when it was in my hands. I have pictures if anyone is interested. The 1pc. is great. I am perfectly smooth all the way up to about 78mph, then i get a little tickle of a vibration from the rear end. Perhaps a good balance/alignment may help. All in all, great investment. It's a 3 hour job by yourself with a jack and a 101-pc. Craftsman tool set. Unless you're a pro.....

Thanks for the input, guys- y'all rock.

 

Damn son. I did mine. took a few hours, buy all you reall need is a few tools, and a blow torch. I can almost remember the tools. let me know how I do.

14mm for the connecitng bolts
17mm for the exhaust
12mm for the hangers
10mm for the shields

I think thats it.

 

don't forget to add two 6mm skinned knuckles- and a 17mm laceration on the right wrist from when the exhaust hanger bolt finally breaks loose and the wrench handle hits it.


hahaha

 

Looking in your sig RuZZeLL, there is no "cheap exhaust" for the Z, well unless you want crap. I got the Veilside Explosion from AMZ, sounds perfect. Also other good exhausts are labree, b&b, sebring, hks hi-power, etc..

 

labree/sebring
not labree, sebring

when i get my exhaust in, im gonna be replacing the u joints on my driveshaft.
ive noticed a little bit of a vibration in lower speeds and a few clunks every once in a while

 

currently i have an OEM rusted-out setup, and they rattle when you shake 'em. the H-pipe has holes in it from rust as well.... so really anything would be an improvement. i hear there are shops that throw away stock setups because they have so many of them laying around.....?

i'd love to save someone the effort of dumpster-fying a decent oem setup