I just recieved a new (rebuilt) starter from RockAuto and looking at the two side by side it looks exactly the same except on the back end there is a terminal stud with a nut on it. My other one doesn't. The rest of the terminals match up. It's off of a 2 door- 2000 Blazer 4.3. I checked the numbers for the one they sent and it checks out and all paperwork shows it's for my truck. Does anyone know what this "xtra" terminal might be for?

 

Mine has that as well I think it might just be a ground... but not in use on mine.

 

you dont need to connect anything to it

It could be a switched positive or negative

I have a OTC test light that tells me if a circuit is positive or negative
OTC 3631 Heavy-Duty Logic Probe Tester - Test Light | Circuit Testers, Short Finders

 

on old style selonids for the old style ing. systems the extra terminal was too throw 12 volts to the coil for a little hotter spark on starting as the coils only normally received 6 volts by a restive wire

 

Thanx for the replies- another question- when we put it on, there is about a 1/4" (or less)gap at the bottom of where it goes into the flywheel--is that right?? We didn't pay attention to the one we took out. Won't water and such get in there?

 

there is usually a small gap around the outside
nearly impossible to get all surfaces to mate
Sometimes you need to shim the starter away from the flywheel and that gap would make it possible