transmission problems or so
 

i have a 99 galant gtz and i was wondering if anybody might know what the problem i'm having is.
when i'm in drive 4 and i'm slowly accelerating between 40-45 the front end shakes really bad like the motor is about to fall out, it also does it in drive 3 between the speeds of 20-30 and it only does it when i slowly accelerate not when i accelerate hard and only between those speeds in those gears. i have new tires front end alignment and the tires rotated stumped any help would be great