THANKS FOR ALL THE ADVICE !

the noise is pretty constant - the faster I go, the louder it gets (I can hear it more when the windows are down), once I get rolling at a good speed, I can put the truck in neutral and the noise is still there (doesn't change the sound at all)

I pulled the filler plug the other day to make sure there was enough fluid, and oil came out right away so I know it is full. There was a little metal on the end of the filler plug (guessing it is magnitized), but it didn't look like a ton of shavings ?

sounds like I will start with changing the fluid in the differential and see what happens - I would be stoked if that will keep it going for a few more years

it only has about 125,000 K on it right now

thanks again

Stan The Man