Bringing this back up again, because I finally took the time to inspect this.
I took the base (and plate) out of the table and inspected the gears that provide the depth of cut. I manually removed most of the sawdust it had accumulated and sprayed both the teeth on the motor and the gear mechanism on the base with WD-40 (don't have dry lube on hand). Doing this gave me really great results both with raising and lowering the motor.
Except that the motor slips at certain points. In fact, it's almost predictable. I can raise the motor almost an inch before it gets a little hard to turn and then the motor slips down nearly the exact amount I just spent the time raising it on. It's only raising the motor, never lowering it. I'm not sure the spring fix bob mentions will fix this, because the lock sticking isn't what is attributing to it in my opinion. I could be wrong, though.