Just FYI, the correct term is Giubo, a contraction of the words Giunti Boschi (Boschi Joints), where Boschi was the name of the Italian engineer who invented this sort of rubber flex joint. It's pronounced "jew-bo".

No giubo's anywhere on a Z, or any other Japanese car I'm aware of. Common on Italian and German cars, though.

 

I have the SAME problem. between 2 and 3 k my shifter and trans rumbles like a bit*h on deceleration. I'm thinking ujoints or trans mount? also a loud vibration when I turn the car off (intermittant). I have already replaced my diff mounts with polys and it helped take the shutter away, but above problem is still an issue. anyone find a solution??

 

I urethane mounted my diff and Trans mount still have the same issue and now it's worse

[QUOTE=cmoose11;7166971]tire balance would be a lot different and would be speed related not rpm.

i know it is the drive shaft vibrating but i'm wondering if it is just rear diff. mounts that i have to change, maybe get some solid mounts? I have read that the mounts are

 

Just to add to this, I have the same issue, with solid diff mounts, trans mount and engine mounts and things still vibrate heavily, specifically after pushing the car then coasting or downshifting and letting rpms drop. I don't think changing any mounts will help any of you

 

+1 I've replaced all my bushings (solid diff bushings + brace), poly engine and trans mounts. Even swapped the DS out with an aluminim unit... no change. It only gets worse with new mounts since there's less to absorbe the vibration. It was so bad with the trans mount it felt like going over rumble strips, so I put the OEM back on.

I think whoever mentioned the flywheel causing it may be on to something. I never noticed it when I had a lightweight flywheel... only after I went back to OEM and put some miles and drag racing abuse on it.