r0to-D3wd

I'm a newbie to the rotory world so this is a little different. I have a 1983 rx7 gsl, this car runs great the only problem is when revved over 3000rpm it start shaking/vibrating , also when driving and when the engine revs when down shifted around 3k and above it does the same. I can feel it mostly when my hands on shift ****. My throw out bearing spins a little bit when clutch released could that be the prob?? Helpp any thoughts would help, thanks!!