Knocking noise from rear above 3,000

Don't Look Back
09-07-2004, 11:26 PM
I noticed twice while driving on the parkway above 3,000 RPM's that the rear starts to knock, sounds like it does when it goes over bumps. On other roads above 3,000 it doesn't seem to happen, am I safe in assuming its just the bumps on the parkway happening more quickly above 3,000?

Sounds stupid, but I want to make sure.
Thanks,
Keith