04 Tacoma Humm/Whine while in Drive/Reverse and stopped. Normal in Neutral/Park

What is your question?

The RPMs drop every time I stop while in Reverse and Drive and a loud humm/whining starts. Goes away when I accelerate, put it in Park, and in Neutral. No "Check Engine" light, or any indicator lights on. Headlights and dash slightly dim when the RPMs drop and humm starts.

What makes this problem better or worse?

Acceleration and shifting into Neutral or Park makes it better. Stopping while in Drive/Reverse makes it worse.

How long has your 2004 Toyota Tacoma had this problem?

2 months +/-