as the post says, I need to isolate a sound that is made in my drivetrain.

sequence:

4-5K miles ago I regeared my gsr tranny. I reinstalled all the bearings on
the main and counter shafts that were inherent to that tranny with 94K.
the tranny was very clean, only highway and no racing.

a couple miles down the road I have changed a clutch disc and then about
2000 miles later I begin hearing a sound similar to that of a lathe hitting
a peice of metal at about 5800rpm under load.

the sound has not gotten louder over the 500 miles or so I have been
experiencing it and I have not driven it hard to aggravate it, only to
try to isolate it.

things I have done to try and isolate it.

put it in gear - make sound, take it out of gear, rev engine while moving
still there, less pronounced. (the sound is only present under acceleration
part or full throttle over 5500 rpm and it doesnt fluxuate much when
the load is altered.)

remove all belts but timing belt and drive. still there.

change timing belt and water pump at 98K. still there.

two things I think it might be. since the gears spin with the engine when
you rev it, I think it might be a tranny bearing or a strange exhaust leak
or the only other thing - a failing oil pump?

please advise. thanks for any help in advance.

 

freaking weird. I did an oil and filter change and drove on it 15 miles and
it went away... for now... I am more concerned that it went away and
what that could mean.