Grinding can be a number of things.

First, run your fingers around the back and front of the tub to machine seal. To see if something has jammed between the tub and frame (bra wires are famous for this). Be careful in case the object is something sharp.
If nothing is jammed in there you will have to open it up and find the cause.

Next at the top of the list would be the front support bearings.

Check for any signs of the drum rubbing on the frame.
If all OK check all the parts that move including the blower wheel assembly.
It is not uncommon for something to fall down the filter chute into the blower. It is easiest to get to the blower from the back but you will still need the top off.

I guess it depends on whet you consider a major job and how hard it is to find the cause.
I would not replace a dryer just because it is grinding.
While you have it opened up you may as well check all moving parts and seals.
May as well give it a bit of an overhaul.
Also check/clean your vent system.