[Raptor]

Actually, I doubt if that will be the case. 20 years of metal work and there are a few things I know. Metal that is sitting in fluid or at least continually bathed in fluid will not get hot enough to change it's temper usually with the exception of bearings. It takes heating steal to a color of at least dull red then slow cooling it to remove temper. It really depends on what the material is that was in the fluid. If it is magnetic, it could be gear material or bearing material. If not, it could be case or synchro material. Really depends on where it is coming from as to how bad of a problem this is. With it being a manual tranny, I would expect the particles are coming from metal to metal grinding somewhere rather than metal fatigue.