Hey guys, I searched for this and found nothing. I have a 94 4runner with a 22re and manual trans. When its wet outside from rain or melted snow, I downshift gears and get a loud screaching from the engine compartment like a bad fan belt. If I rev up the motor, it will usually stop. I haven't changed the belts for a while, and there's never any water in the engine compartment or on the belts/pulleys. I'll be changing all of the belts soon and hopefully that'll do it, but I was just wondering if anybody knows if theres a possibility that something else may be going on. Maybe in the tranny or running gear?

 

probably the belts. The cold and humidity may be causing them to lose their grip on the pulleys. Revving the engine warms the belts back up again.

 

My guess is the belts too. Spray some belt dressing or silicone on the belts and see if it goes away. It won't last but it may confirm your suspicions.