The funky shifting could be the shift shaft seal.
This might be a perfect example of why I don't replace those springs unless they are broke. From my experience I bet those springs were replaced during the last recent rebuild. I would guess much more than half of the broken springs I have replaced were just recently installed. I haven't rebuilt nearly as many trannys as robtg, for instance, but I have never run into any problems leaving good springs in there. I think you are better off not replacing them.