lately my truck has been making this metal scraping noise when i decelerate. it's audible in 1st though 4(may be in 5th, but at that point im going above 50, so i really can't tell from all the other noises). it goes away when i give it gas or i push in the clutch. also with the clutch engaged(or disengaged?, whenever it's mated to the engine) but in neutral it doesn't seem to make any noise either.

What could be the issue? i'm thinking either the pilot bearing or the input shaft, but i'm not too familiar with manual transmissions. i just put some new pennzoil syncromesh in it, so hopefully that will quiet it down a bit.

 

I think you mean throw-out bearing or thrust bearing. The pilot bearing is a tiny roller bearing that fits in the rear of the crankshaft and wouldn't make near enough noise. It could also be bearings in your trans itself. How old is the clutch? Might be time to do it so you know what's all going on in there.