Loud exhaust at high speeds...?
 

Hi everyone! Just wondering if anyone can help me pinpoint what I assume to be an exhaust problem. Dodge caravan 2003. Sounds good for the most part...maybe sounds louder when you hit 80kmh (48ish mph) but you need to be listening for it. The real problem is when you hit about 110kmh/65ishmph. It really starts to get loud and if you push it to 115-120 low 70smph its very loud and when you hit that mark theres a metallic vibration noise that starts and disappears as you accelerate oast that point. I only drive in the city for the most part and didn't notice it til this morning.....when I got on the highway to start a road trip (of course).

I'm pretty handy at muffler repairs but before I get under I thought I'd ask here first to know what to look for.

Thanks for any advice!