mufflers have fan pins on the inside, one could have broken off and once you get to a certain speed it would rattle
Check your muffler pipes.
Muffler Heat Sheild
Percussions ... snare drum, perhaps.
Actually, mufflers ate the thing that quiet your engine. If you hear a deep sound, you likely need a new muffler.
The rattling is usually caused by the muffler vibrating against the car frame, more than likely because of a torn or worn brace. Braces hold the muffler and tailpipe(s) away from the frame to prevent vibration and damage. The loud sound may indicate a rupture in the muffler itself or somewhere along the tailpipe. If your brother said that the pipe isn't rotted, it may be the muffler itself that has a hole in it.
check your exaust system including headers,pipes,cat if still on and the muffler there is a possiablity that the muffler A. has been damaged and has a hole in it or B.it has a preformance muffler on it causing the annoying sound or C. the other parts have holes in them and are letting exsive sound pass out * it sounds as if a fart_can has been installed on it,take it to a muffler shop
could be air in the pipes. Makes a banging sound until the air is released. Look for a valve
A hole in the muffler would cause a knocking sound in your muffler. A loose exhaust pipe can also cause a knocking noise.
as far as the humming noise and the grinding noise it sounds like your power steering pump is either out of fluid or gone bad completely. as for the muffler? ?MAYBE? the strain from the bad power steering pump is overworking the engine causing it to make noise? answer definetly a bad steering pump as for muffler, the sound can be transfred and magnified on a car, replace steering pump before bothering about the muffler sound may be gone
Only if it has 8 cylinders, anything less than that just makes it sound like an out of tune lawnmower.
A rattle snake
I've had this same problem and if it makes a rattling sound it sounds like its the catillitic converter.