Whining noise

I have a 95 voyager 3.0, there is a whining noise coming from, I guess the transmission. It slips a little shifting into 3rd and sometimes down shifts on the highway. Any ideas ...please help

Sounds like a transmission problem to me. Take it to the shop and have them drop the pan, watch them do it. Ask to see the bottom of the pan. There should be a magnet in the bottom of the pan. Check to see if there are fine metal shaveings attached to the magnet. If there is shell out 1000.00 to have them put a rebuild kit in it. Thats my guess.

check the noise for location and response to speed. My fuel pump has started to go out, and it emits a steady tone when the tank is below 1/2. Who knew that it was in the tank?