vibration while stopped in gear

when Im stopped at a red light my truck starts to vibrate, when I shift to neutral or park it stops, also stops when I start moving. Only happens while stopped in gear. Any help would be appreciated.

thanks

 

Welcome and sounds like a transmission issue.. Not sure exactly what it could be tho

 

damn, was hoping it would be a quick fix. searched and seems a lot of people are having the same issue. when stopped idle drops and vibration occurs, speeding up or taking out of gear stops the vibration. nobody seems to know what the issue is

 

I've had that for a while...(since the early 40k ish miles)

I'm at 100k now and still does it every now and then but still wonder wha it could be

 

guess I'll take it to the dealership, will they diagnose for free? or do you recommend somewhere other than the dealership?

thanks