All of a sudden I heard a high-pitch sound when I was stopped. When I open the hood, the noise is coming from the rear. When I let the clutch out it stops. A few days ago my clutch felt like it was slipping a little while engaging, but holds when let all the way out. It's a dual friction. Any ideas?

'89 3.0 4Rnr: Jacob's Electronics, K&N, CF Dual Frict, 4:56 w/ Truetracs, 33 BFG AT/KOs, Cascade Audio, Pro-Comp 4" susp & 2" body (previous owner)

I know, a lot of wasted time and money ... if I knew then what I know now....