i think i have an aftermarket clutch my truck is an early 04 6 speed the pedal is pretty stiff and if i put in second and just let off the clutch and just let it idle it makes this weird rattle noise what is that noise and how can i tell if its an aftermarket clutch or not

 

Not sure about the after market clutch but you may be experiencing U-Joint failure. Do you also get a squeaking noise? Does it happen again when you shift to third and start to accellerate? Then disappear altogether at higher speeds?

Mine is doing this and I am going to take it in on Monday and get it checked out. I had a Ranger that squeaked and then vibrated a lot at highway speeds, when I pulled the U-Joints a lot of the roller bearings were just powder.