Someone in an astronomy forum said the same thing - thanks.

I don't think the four screws are for adjusting a reticle. They are tightened all the way down to the cast body of the transit, as opposed to adjustme...

Thanks, Anvil. To be clear, I'm not sure anything was loose that isn't supposed to be when I started to remove the 4th screw. But I guess it could be....

Here are four photos - one of the whole transit, a closeup of the eyepiece end, one with a small screwdriver pointing to a single small brass screw, a...