We have a 350Z when there is power to the wheels it is ok when you slow down and it gets to a lower speed there is a bad vibration and it feels like the back wheels are jumping up and down. it seems like a universal but I can't find any thing. with the drive shaft or back axles. The place the drive shaft is located makes it hard to check but they seem ok . Any help would be greatly appreciated

Pa

 

welcome and start by jacking up your Z and supporting it on a level surface with jack stands. Do a full inspection of the rear by pulling the wheels and checking the rear wheels. lug studs and wheel bearings for play. If nothing there, move further inboard and inspect the rear axles. Axle to diff bolts should be tight and you should also check the 14 mm nuts and bolts on the CF driveshaft yoke to diff for missing or loose hardware. My bet is you'll find your vibration somewhere in there.

Be sure to come back to this thread and update us on what you find.

 

As dkmura says, check everything rear of trans.

But a couple of quick troubleshooting questions...

When you are slowing, is it under braking or coasting down from speed?

Also, if you declutch at that lower speed (or neutral coast) when it starts bouncing, does the sound/feel go away?

Does it behave this way every time you drop speed?