Clutches can cause shutter. The equivalent in an auto is the torque converter...which is one option. i don't know how to check this. Though you probably need it on a lift and listen with a stethoscope as you run up wheel speed (off the ground).

Another idea is a motor mount. Check for engine play when you rev up in park. Or put foot on brake in drive and have someone else look at engine shifting.

On mine, the u-joints weren't so much "worn out" as binding as they rotated. You could hear them at hwy speed. you can probably rule this out.

Places like NTB and/or Certified Transmission perform diagnosis for free! :-)