I am starting to have a bit of trouble with the starter on my T100 3.0L V6.

At times when I turn the key, I hear the solenoid click but, the starter motor won't fly. After the click if I hold the key the clock and dash lights will dim, so power is going somewhere. If I keep trying sooner of later the starter will kick in and then it seems fine.

As the battery was old I replaced it and I still have the same problem every now and then and the frequency is getting higher.

I'm thinking starter or solenoid. Is it worth taking the state apart and cleaning the commutator. Will a dealer have new brushes or do I just need to forget about trying to solve the problem and just replace the starter? Could the solenoid be corroded and just not sending enough current to the motor?

Autozone has starters for about 150 with the core.

L