Have a vibration 1100 to 1800 rpm in 4.3 2wd extended cab. Any ideas on whats causing it?
And what is a transmisson shutter?

 

could be a driveshaft balance problem, or u-joint worn. check the rear driveshaft for play at the u-joints, then get your driveshaft balance checked.

 

the v6 4.3's have vibrations in the exaust... I believe the cats are where its caused at. I had my exaust done, and it solved that problem.... Other than that, you can take it to the dealership and they will add wieghts at cirtain points to "balance" the vibrations... Good luck