Well yet another problem with this truck!!!

I have a bad grinding noise, like metal grinding metal, over the past week or so when I let off the gas pedal, especially when gearing down to 2nd and 1st I hear it and it sounds aweful. As soon as I press in the clutch it stops, let out the clutch it grinds, and so on. When in neutral coasting its quiet but I think i might still hear it a bit. I checked my universals and driveshaft and it's not them.

What do you guys think this grinding is? Pinion and/or carrier bearings? Wheel bearings will grind but since the noise stops when I press the clutch that rules it them out right?

I am so pissed off at this truck right now cuz it's been one problem after another this year and is costing me out the ***. If this is a pinion or carrier bearing problem how time-consuming and difficult is this to do? And is it expensive?

Please if I could get any advice that would be sweet. Im at a loss of what to do right now as I cant afford any more huge mechanic bills right now. But I dont want to do more damage.