Rattling under the car

[shlby123]

hey everybody! Kinda new to the 300Z but Im trying to figure out a problem with my '90 300Z with an auto. transmission and about 90K on it. When I first drive the car to work in the morning it's ok for about 10 minutes without any noise but AFTER about 10 minutes and then on for the rest of the day, there is a rattle under the car when I try to accelerate. My first guess is obviously the transmission. I believe I've heard a similar noise when I was having probs with the transmission on my mustang, But the car still shifts very smoothly and all...it's just that the hard I try to accelerate the louder the rattle is....and then when I let off it reduces down to the point where I cant here it all? I guess what I need to know of this is an indicator that my transmission is shot? Or is it possible to save it?

[elwesso]

i doubt its the trans if it operates as it should...

my guess would be that its either a heatshield on the cat or the cat itself.