When you put your head below the floor boards of my rig, when its idleing, there is a clickity tick tick sound coming from the transmission area. 
it doesnt get worse with speed and the truck drives fine.
what could it be?
Don't worry it will go away when you buy the new transmission..
Sorry had to say it... Try some lucas gear oil in the transmission.. If it's not a loose heat shield or something like that.
