Transmission/Driveline jumping/vibration

[barnum]

Hello all,

Problem:
I own an 02 Pathfinder SE with a manual transmission. There is a bounce in the shifter/transmission when crossing speed bumps or dips in the road. It seems most noticeable when in neutral and is independent of clutch pedal position (depressed/at rest). There is a chattering felt in the shifter as if the transmission is bouncing and the contact of the shifter to the transmission shaft is causing the chatter. I have also noticed a slight chatter feeling when in gear going down a hill with 0% pedal position a.k.a. when the engine is no longer driving the wheels but vise versa.

Extra info:
Clutch was replaced by dealer/mechanic just prior to purchase. U-joint at rear transfer case output shaft/driveshaft connection has no play in one direction and ~1/16" play in the other. No "typical failing U-joint" symptoms present. When dealing with U-joints in the past, there was no noticeable vibration in the shifter/cab, only the classic clicking under certain driving conditions (certain vehicle speeds, slowing down to a stop, etc). No engine movement indicative of bad engine mounts. Can move transmission slightly with moderate force applied the bottom of its housing but no visible cracking/wear in transmission mount. No good place to mount camera within view of transmission mount to do test drive and review video (dual exhaust pipes at crossmember w/ dual cats). There is driveline vibration from 3500-4500rpm but I believe this is just engine side since it'ss repeatable in every gear including neutral and I've seen Nissan literature of needed engine vibrational improvements for VQ35DE's successor.

I'm looking to see if anyone has experienced anything similar on a Pathfinder or any car for that matter for possible solutions. My garage is limited so even something like transmission mounts might be difficult so I'm looking for relevant advice (not how someone's brother's mother had a car that had a problem nothing like this) before I start tearing into this project.

Thanks in advance!

[barnum]

No one?