I'm not exactly sure how the quill feed is supposed to work right now to feed the quill down by hand with the big lever on the side of the machibe you also have to hold down on the lever on the front of the head is this normal?
I have a wells-index 837, which may be a bit more Bridgeport than Index, but with all the mills I've been around the quill is like a drill press. No other handles required. The quill does pin to the quill shaft and can come out to reindex for better placement. The power feed lever, to the left, engages if the center of the crank is pushed or pulled. Had to go play with mine to make sure I was telling the story right. Power feed is slow though because it's going through a series of gears, not direct drive like a drill press. Also, when engaged and the mill is not running, the quill would be locked up because of the gear meshes. So, your problem doesn't sound normal. Easy fix would be to make sure the power feed is disengaged and the quill is engaged to the handle. Worst case is the quill shaft that engages the quill (essentially a rack gear system) has somehow disassembled itself. I really hope it's easy, and you can laugh about it some other day.
Had a 745 and no you only had to pull down handle like a drill press. If i remember right under that cover of lever you r holding in is a clutch type assembly. I may be mistaken ,it has been a long time since i rebuilt head on that machine and i sold it several years back.
Good deal and thanks for the follow up, was wondering if you had found something. Stuff like that can drive you nuts sometimes. We kind of follow what is there, assuming the last guy was playing by the same rules, as we dive into the unknown and hope a spring doesn't fly across the shop. Then you have to figure it out. My speed indicator wheel on the head always read backwards-showed it was slowing down when it was speeding up. Someone had installed it with the chain pulling the belt drive speed adjuster "over center " the wrong way. Backed it up around to the other side, now it works like it should. Been putting up with it for a long time, figured I'd get there. The other day was the day.