It is possible that misalignment between the starter and flywheel is
torquing the Bendix shaft (which caused the problem with your old starter).
Otherwise, you may have gotten a defective rebuilt starter. Happens all the
time, and should be covered under warranty.

The Bendix should engage the starter even when there is insufficient voltage
to crank the engine. The battery and/or cables are not likely to be the
source of your problem

--
-Elliott Drucker