[NitricWave]

Might be worth safely getting under it while someone else holds it at 2500 rpm so you can pinpoint the problem before spending money.

OP - Here's a thought.

Have a friend or someone else get in the car and hold the RPM's and you get under and check.

When I first got my 16' R/T I had a similar noise and thought it was coming from the back of the car. Turns out it was a heat shield in the middle of the undercarriage that was just barely tapping the pipe. They are a very pliable material and can easily be bent.

Otherwise, depending on your speed at 2500 RPM, after 4th gear, the car will go into "lockup" through 8th gear. That can cause a burring type noise for a second or so.

Hopefully you can figure out what it is before taking it to a shop and them throwing hours at it only to find nothing.

Check the exhaust hangars, the heat shields, molds under the car, etc.

Thanks for the suggestions, I do plan on doing this before I take it somewhere hopefully it's a easy fix and not a cat.

 

[bbuff4]

Every since I've owned this Durango I have had a rattle that is only present at 2500RPMs, I am not able to tell where it is coming from other than it's coming from the rear of the vehicle. I have looked under it and have not found any conflicting heat shielding. This noise has never gone away and always occurs at 2500RPMs (In any drive gear). If anyone has had any experience with this at all or any ideas as what could be causing this I would be extremely grateful. I have attached a audio sample below.

,Thanks

Unknown Rattle Noise

I had a noise issue once that only seemed to present itself above certain speeds. Turned out to be a loose mud flap/guard.

 

[NitricWave]

I thought I would update this for anyone else with this weird issue. I ending up putting about half a inch of washers in-between the rear resonator and pipe and that has pretty much fixed the issue for a few months. Here's a better picture detailing the area.