Check the trans mount. 

Might also see what the trans sounds feels like w/o a load on it.  If not familiar with testing the trans this way, you put the transfer case in neutral, and shift through the gears with the engine running, revving and shifting as if you are driving.

I will try that tomorrow. I've also been told twice it could be a misfire. I didn't believe it because it seems fine with tans in neutral but second guy said I might not be able to feel it until there is a load on the drive-train. Will do some tests tomorrow.