These are utilities that have grown through time a provide a lot of value for me but i don't feel comfortable sharing this. Is my employer allowed to ask me to submit this code and give it to them so that other engineers can use it and probably i have to then support it. ?
I ask, "Where?"
Because jurisdiction matters. A lot. Another big question would be whether you developed these utilities on your own time (again: jurisdiction matters!) or on the company's time.
As it stands your question is basically unanswerable.
Do you use or contribute to OSS? If so, then i'm confused why you think sharing it within you company would be a problem?