You won't really know untill you get it off and remove the rear cover. Some are soldered and some have a machine screw and nut. If soldered you will need professional carbon arc
. Either way if you can find a local shop to do a quick fix and look for any other parts
that are worn. You should have a minor repair. This would be a good time to replace the solenoid and drive gear
and check the front and rear bushings and the brushes
and brush springs.
Remember when you re-install the unit that you only tighten the battery
cable nut on the solenoid to 1/2 turn before it breaks! Some fellas will tighten it till it breaks and then loosen it 1/4 turn...this is tooo tight and will cost you another solenoid. :-)
Just some shop humor