1999 wj Laredo weird whistle
 

I have a 1999 jeep wj Laredo with the 4.0 with a strange whistle coming from under the vehicle, not in the engine bay. Any ideas. Took this video of the noise. https://www.youtube.com/watch?v=MB9IGPOkIpo

Not in the engine bay... When does it happen, and not happen? When the vehicle's moving, when it's under acceleration? When it's stopped, idling, etc.

​​​​​​​Which side does the sound come from, or does it sound like it's underneath?

It is coming from right underneath towards the rear axle-ish area. Happens when engine is idle or when I am coasting, when I am driving it straight up just disappears.

Thanks. Sorry, I couldn't hear the video, where I am it's terrifically bright and windy, and I can only stop for a bit.

All good. Any ideas? Possibly just needing exhaust work?

I'm just guessing here, but could the tailpipe be dented just enough to act like an organ pipe? As in resonate at just the right flow?

I never thought of a dent, I'll have to take a look tomorrow. But it seems to happen very sparatically recently every day, but before it was maybe once a week... so it's not every time just a majority.

The only other thing I can think of, if it's the exhaust, is a loose muffler baffle.

Can it do Amazing Grace? or the Mayberry RFD tune? I just love that....

Almost just needs more practice or, it's a little out of tune.

Thanks for all the suggestions I'll have to take a look once it gets warmer out! It's cold as hell here.

Update: so mainly can hear it from the rear. Very random when it occurs sometimes when it's hot, sometimes when it's cold... also I can hear it slightly better from the rear of the vehicle on the side opposite of the exhaust. Could be from just the absence of exhaust noise. Any ideas? Looked for any obvious cracks, dents, ect... nothing too obvious so might have to take a closer look.

Anymore ideas anyone? Also does anyone know if exhaust leaks are very expensive as I have never looked into it and have never needed exhaust work on any of my previous vehicles.

I don't know but, maybe it's the electric fuel pump in the gas tank or even the gas cap vent whistling. Try taking the fuel cap off with the motor running and see if anything changes.