Engine, transmission or muffler problem?

engines
transmissions
#1

I have a 1998 Toyota Sienna minivan and it has ~155k miles. It was running great until recently. In the past one or two months, when I put on gas pedal, I hear a loud continuous noise that I never heard before. It seems to come from front. When I take my foot off the pedal, the noise goes away. It appears to shift gears up and down OK. What are the problems? engine, transmission or muffler?

#2

Probably need a bit more info in order to diagnose this one. Rocketman

#3

Just the word “noise” does not really tell us much. Could you describe it? Could it be a heat shield ?

#4

To eliminate transmission while in park or neutral rev the engine and see if noise is still present or not.

Describe the noise.