In my experience,"rod-knock" is usually more prevalent when engine is idling. If bearings aren't too-far-gone,the rod knock will be substancially quieter,or dis-appear when "under-load" If the knock quiets-down, when you let the clutch out,with your foot on the brake, the crank MAY be salvagable,so shut her down,pull the pan, remove,(in sequence),mark,(with masking-tape,and "Sharpie"), all the bearing-caps. Check the bearings,and the crank for scoring. Even if crank "looks O.K.,I'd still plasti-gauge the journals,to make sure they're in tolerance.you put the gauge between the bearing and the crank,torque the bearing to spec's,loosen,and remove cap,and the "spread" of the gauge reflects the clearance between the two. Test and record all bearing-caps' measurements. If crank is still "in-tolerance",I believe,(Not 100% sure),that you may drop the crank,(May need to jack the engine for this). If the journals are slightly scored,but not grooved,or gouged,i have been successful,using emery cloth to restore the surface. Just make double-sure surfaces are surgically clean before re-assembly. This will help prevent pre-mature wear,which would bring you back to this post way too soon. Hope this helps.
