Have you checked the fluid in it recently? The reason I ask, is because on the manual transmission there are 3 rubber plugs on the back and over time they shrink, become brittle and the fluid begins to leak out of them. I would recommend changing them either way since it's not extremly difficult. A 5/8" metal freeze plug fits in there perfectly and you never have to worry about it again. My F150 began rattling, thought the pilot or throwout bearing was going out. After checking it was low on fluid and those plugs had shrunk.
Boredom is the desire for desires.
Stays crunchy ......even in milk