To understand a whine from the drivetrain, compare it under normal, safe conditions: cold versus warm, idle versus steady speed, and light versus higher load. Record whether it follows road speed, acceleration, or deceleration and which direction the sound seems to come from. Change one condition at a time so the result stays useful.
Do not create a risky test just to reproduce it. Note tire changes and recent axle or differential work; sound can travel through the body.
Quick educational note
For information, not a diagnosis or repair instruction. Vehicle-specific checks are still required. Consult the manufacturer's guidance and a qualified technician.
How to use this information
This article explains general principles and does not establish what is wrong with your vehicle. Read the content limitations.