Ok, Something is making a grinding noise when coasting at higher rpms in fourth and fifth gear. I'm pretty sure that its not my transmission (I just got a new one from Marlin), and I saw on another post that it could be my pinion bearing. It does kinda sound like a bearing noise and I do have a bit of a driveline vibration. There isn't a whole lot of play in the bearing though, so I was wondering if it could be something else. Its not really irritating, so I might just wait until it gets worse or breaks, then I will know for sure what is wrong with it. Any suggestions would be appreciated. I've already done the whole jack it up run it with the tires off the ground thing, and the noise seemed like it was gone or at least a whole lot quieter.