Originally Posted by NoHaveMSG (Post 3292712)

If he jacked up the motor to squeeze the mounts out it may have shifted the exhaust around on it's hangers to the point it is touching somewhere.

I am on stiffer engine, trans, and diff mounts with no rattle.

Originally Posted by ActionMaxon (Post 3292716)

Did your engine vibrate much before the new mounts?

nope

Stiffer mounts could cause engine vibrations to harshen, however it would be felt in the body, especially steering wheel due to the proximity of the engine mounts and rack mounts.

definitely vibrating a lot more with the new ones

If your engine is more "locked in place" that would mean your exhaust should be receiving less vibrations.

I agree with above. Sounds like an install problem.

I haven't worked on exhausts on this car but on, at least the later model subies, there was a tab on the exhaust near the catalytic converter that attached with a single 14mm bolt. The body side mount itself was designed in a way that you could undo the bolt and the exhaust would still hang there because the mount had a sort of catch. Horrible explanation I know.

Anyway, that bolt had to come out in addition to unbolting from the heads to lower the manifold any. Maybe that bolt was not reinstalled?

Possibly this is the case and you're hearing your exhaust bounce around on that mount? That would sound like it's right under you though so maybe not. Just a thought.

Maybe someone who has actually had the manifold/cats off these cars can say if this sounds familiar.

Other than that yeah, maybe something got tweaked or a bolt did not get tightened.

Can you shake the rear of the exhaust by hand and hear anything?

Originally Posted by StraightOuttaCanadaEh (Post 3292721)

all he told me was that he had to remove the headers to do it. I also have the trans and diff mounts. Good to know! thanks

Originally Posted by NoHaveMSG (Post 3292724)

If it is coming from the rear, I would check where the catback routes under the subframe. If it is coming from the front check FP/OP clearance. I had issues with both these spots, had to loosen and shift stuff around to make sure it didn't touch. I also had clearance issues with my diffuser. So if you are running one check to see if the bottom of the muffler is hitting there. Mine does trap road debris(including part of a skunk) in there.

Originally Posted by ActionMaxon (Post 3292716)

Can you shake the rear of the exhaust by hand and hear anything?

Originally Posted by ActionMaxon (Post 3292716)

I haven't worked on exhausts on this car but on, at least the later model subies, there was a tab on the exhaust near the catalytic converter that attached with a single 14mm bolt. The body side mount itself was designed in a way that you could undo the bolt and the exhaust would still hang there because the mount had a sort of catch. Horrible explanation I know.

Anyway, that bolt had to come out in addition to unbolting from the heads to lower the manifold any. Maybe that bolt was not reinstalled?

Possibly this is the case and you're hearing your exhaust bounce around on that mount? That would sound like it's right under you though so maybe not. Just a thought.

Originally Posted by JBezugs (Post 3293132)

So I’ve had an annoying exhaust “knocking” sound that would make noise when reversing and steering, or putting the e brake up when parking after driving the car that was coming from directly underneath the car (like the trans tunnel area). It happened right after I got my header installed and was exacerbated slightly when switching one of my exhaust hangers to an extended hanger to level my exhaust tips out. I went through the entire exhaust section and everything was tight.

My car is currently stored for the winter but I will be sure to take a look at this as soon as it’s back on the road in the spring. Thanks!

Originally Posted by StraightOuttaCanadaEh (Post 3298319)

Fixed the rattle today. Turns out it was a loose bolt at the front pipe/trans area just like a few of you said. Thanks guys!