An odd grinding noise?

[Spartan040]

This isn't related to an E-body, but I thought I could find some help here. I have a 1986 Dodge Ramcharger with a 318 and 727 (or 904, not sure which) transmission, and lately I've been hearing a grinding noise coming from somewhere behind and underneath me when the car is idling at low RPMs. It sounds like it may be something with the transmission or the driveshaft? Should I be worried about this?

[blown motor]

Unusual noises certainly need to be diagnosed. Get a friend to listen from outside the car. Sounds can travel through your car and they are not always coming from where you think. I know from experience.

[Bullitt-]

I'd imagine it's still grinding at higher speeds, you just don't hear it over the road noise.
Put it up on jack stands n run it in gear & see if you can't isolate the issue.   

[Spartan040]

Unusual noises certainly need to be diagnosed. Get a friend to listen from outside the car. Sounds can travel through your car and they are not always coming from where you think. I know from experience.

Will do