they are Ford manufactured starters, if you listen to an 80s or 70s Ford start up, they sound exactly the same
It's normal for the corners of the teeth to be missing at times, as long as the tooth is still mostly intact. If you're missing entire teeth or large portions of teeth, you have a problem..
The joys of working with automatics x_x Struggled for a while to get the dipstick tube back into the tranny of a 2000s suburban I've been in the process of replacing the engine in... After pulling the tube out a quart of fluid came with it and it took three sheets of cardboard to keep from getting soaked in the stuff.
You can just leave the transfer case in 4x4 all the time, because it's really awd, just with the option to go to 2 wheel drive. it can be driven indefinitely, at any speed, in full time without a problem, and won't really hurt your mileage much. Considering the time of year, I'd just leave it in 4 wheel... Though, you'll have to lock the front axle in place, which is very easy to do...