There's a rattling noise coming from my passenger rear everytime I go over a hump or uneven road. I just got my muffler and the exhaust pipe done recently, so I assumed its the loose muffler. I got it checked out and was told the exhaust was all secured, the mechanic didn't hear anything as well. The noise becomes louder when the car is fully loaded with passenger. What can be the cause of it?

 

Mine does that as well. The exhaust pipe just in front of the Muffler is hitting the rear "axle" at full travel when fully loaded. I can see on mine where there are marks on the pipe.

My rear shocks are new, so I know I am not bottoming out.

Solution: no fat people in the back seat!

 

Most commonly it is the muffler/tailpipe hitting something. Less likely, but possible, is a strut coming loose.

 

Why would the weight make the sound more noticeable? I replaced the passenger rear strut mount last month and the strut is still fine (approx.120,000 mi)

 

why would you even bother with the rear mount when your struts have 120k miles?
when the car has more load it sags more, very simple. it probably is your exhaust. with the car cold, see if you can swing the pipe up and down or side to side.

 

The exhaust does have some play when I tried swing them side to side and up and down.

 

Travels farther...

Every since I had the exhaust replaced from front back to the muffler, it hits.

 

these cars are old. i noticed a "chingaling" noise in my s14 similar and couldn't figure out what it was until i went to paint my fenders. it was a loose tab of metal (an old thumb-size bracket for god knows what) that was simply hanging around and vibrating at certain times.

you car has alot of things like this.

 

its supposed to man, thats why we have rubber hangers so it has room to shift a little if need be.