Hello everyone. I just finished changing the clutch and flywheel on my 2004 G35 coupe.. and now there is a strange click/thud noise when I hit bumps (sometimes) and a much more pronounced version of the noise when I brake aggressively. Does anyone have any ideas as to what this could be? It certainly sounds like the drive shaft is sliding toward the front of the car and hitting something, but it's been tightened down.. Also, not sure if this could be related, but there was some light leakage from where the driveshaft and transmission come together on the first drive after reassembly. I think it has stopped leaking now.
Some more details: I tightened the flywheel and clutch (Exedy) to specs, made sure that the transmission was bolted on perfectly, replaced the bolts on the drive shaft when I re-installed it, and double checked the bolts on the cross member that had to be removed to access the transmission. I'm completely out of ideas..

 

I just changed the trans fluid with Redline 75w-90 GL-4... noise seems to have gone away for now. Will report later if it comes back.