Whinning Noise

I have a 87 Dakota with a 2.2 and a 5 speed. I am getting a loud whining noise when Idling in neutral. The noise stops when I push in the clutch. The Clutch works fine when driving the truck. The truck has 104,000 miles on it, and I am assuming it is the original clutch. I did check the fluid in the clutch master cyl and it seems full. Any suggestions would be greatly appreciated!

Thanks
Paul

Have you investigated the throw out bearings? My rattles when idling, father in law says rattling is OK to a point, but when gets too loud, might be time for clutch and throw out bearing. The clutch works great when starting off and driving/shifting.

Just throwing this out. I have a 90 with a 4cyl and 5spd also. I have 78k miles on 2nd clutch.