I've got some Issues... well not me, but my car!

I think you have multiple problems;
A noisy pinion bearing, and maybe a loose pinion yoke
a bent driveshaft,
possibly out of balance wheels,
and you engine idles like it is getting too much EGR,lol.
IDK about the slapping,
unless you don't have a SureGrip, then it could be that there is something wrong inside with the spiders and crosspin.

Thanks for the reply!
Honest questions here, How would a drive shaft get bent? And also how do you adjust the EGR? Not sure If it matters, but this was from a cold start, no choke and I had to feather the gas so it wouldn't die until I put it in 3rd gear to let the clutch out. This noise started out of blue one day. I do think the axle bearings could be bad... I can also check to see if any weights came off from the tire too when I under there next...