Issue 1

Harbor Freighr had a number of cordless drills that were inexpensive,
but I noticed many had no amp rating listed on the box. Even though
they were 18 and 19 v, the drill bodies seemed small, which I assume
in indicative of a small, low powered motor and the fact that the amps
aren't listed anywhere on the drill or the owners manual probably
isn't an accident.

Since I was in a hurry I picked up a corded 4.2 amp Chicago electric
drywall screwdriver - I'm guessing a Harbor Freight store brand? - by
its shape it loos to have a reduction gear assembly for increasing
torque.

Out of curiosity, how much cordless drill do you feel is enough to do
drywall? Not going to be doing it daily/commercially, at the moment
have a couple of walls that need drywalling. I built a sound booth out
of 2x4's, drywall and R-13 insulation using a B&D 4.5 amp 1350 RPM
corded drill I got at a pawn shop and got a drywall attachment from
Home Depot. Seemed to have more than enough power. I've never owned a
cordless so I don't know how the specs translate compared to a corded
drill.

Issue 2

The reason I went on a quest for another drill is that the
aforementioned B&D 4.5 Amp drill has gotten to where it only wanta to
run when the drill is held at a certain rotation, typically with the
handle parallel to the floor. I took it apart to see if there was
anything obvious broken or out of place, I pulled the center armature
section apart from the rest of it. What I noticed were sections where
the armature has what look like wear marks.

Any theories on why the drill is behaving this way and what bearing
the worn spots might have? I assume this isn't a drill that's worth
sinking a lot of time into to fix.

Thanks for all info.