Summerfun

Driving down the road last night at 50MPH in 6th with my Richmond 6-speed,
suddenly heard this sound like a 'machine gun' with the stick shaking in my hand.

Let it go for all of three second and took it out of gear and coasted to a stop....all the while saying bad bad things.
After I came to a stop I gently tried 1-5th and reverse, all seemed fine.

Took off and drove home using 1-5th....no problems.

As soon as I got close to home, tried sixth.....rough sounding machine gun with the stick shaking in my hand....I would guess revolutions of the machine gun sound was about 3 per second.

Any ideas before I yank the Richmond???
Could I keep driving using 1st to 5th?? We have a local Vette cruise tomorrow!! :eek: