loud Rumbling sound from around back area

[A.S.]

I hear a loud rumbling sound when the car is in 2nd/3rd gear. It goes away in top highway speeds and when in gear 1. (The muffler is new) so I doubt its the muffler.

[Kim 95' V6 DK]

it could be the muffler. <BR>a buddy of mine had the same prob. when his car was warm<BR>cuz when the muffler gets hot it also gets bigger and then it could rub against something under your car especialley when shifting gear (take a look at the engine when putting it into gear moves alot)

[supercharged]

Do you have sub woofers?<BR>The bass might be hitting at the exact time that you shift.<P>Either that or youre dragging a small woodland creature, and the 2-3 shift is whats killing it.

[A.S.]

I do, but the sound is there even when the subs are off. It is starting to sound like a hole in the muffler. I'll have to go under and look.