slight seat vibration

[paintman61]

on a90 300zx 2+2 driveshaft's ,did some engine work now have slight vibration at highway speed coming from seat area. the rear driveshaft has a letter
F stamped on one end,which way,should it face, front or rear. i know it sounds dumb but someone had repaced clutch before.
thanks 4 info.

[Metacom]

From what I understand in your post, you did some engine work that did NOT involve removing the drive shaft? I can't comment on what could cause vibration felt in the seat from just engine work.

If the drive shaft was removed, the joint that connects to the differential has to be marked (on factory drive shafts) before its removed and replaced in the same position. It is also possible to install the CSB mount upside down which will cause vibration/whining.

Or maybe your center support bearing just coincidentally started to wear out.

[paintman61]

the driveshafts were removed,i marked them ,but someone had already had R&R them before ,but there is a sticker with letter F on the back driveshaft,should it point forward or does it mean final???

[Ziggy1621]

The driveshaft should only fit one way. Most of the time, the vibrations come from the carrier bearing wearing out and would need to replace the bearing.

Welcome to Nico! Post up some pics of the ride!

[ZX-Smoov]

I had vibration under my seat when under load (meaning I was pressing on the gas). It felt like I was driving over gravel. I purchased a transmission mount from Megan Racing and it solved the problem. Good luck.

[nissanfreak12]

Another option is to clock the driveshaft 180 degrees, see if that helps out.

Make sure the spacers were in between the body and the center carrier bearing, this will also cause the vibration you speak of.

[ZX-Smoov]

Regarding spacers: I may investigate options for that. Thanks for both suggestions!