help motor roars
 

I have a 2001 4runner and recently I thought it was my transmission, but not sure now. At first it sounded like it bogged down when shifting from 2-3 gears. Today while driving i got up around 60mph and the motor started roaring and the whole car shook. It has a little over 100,000 miles and I haven't had any problems with it until now. What could it be?