This question came up in the Online 10-day Retreat Nov 3, 2020, guided by Delson Armstrong. Day 5 was part of a daily 30-minute discussion on the suttas, the Dhamma talk and reflections.
Slightly edited to improve readability
Yes, volition and Saṅkhāra are different. Sometimes the translations will, for whatever reason, say that Saṅkhāra are volitional activities, or volitional formations, or sometimes even equated to intention. But the Pali translation of volition, or what is intention, is cetanā.
The five factors of mentality, in mentality-materiality, are feeling, perception, intention, contact, and attention. Through the faculty of feeling - and that is the six sense bases-, the process of feeling occurs. Through the faculty of perception - that is memory and recognition -, the process of perception and recognition occurs. Through the process of intention, this is how the formations flow through the consciousness. So, the consciousness carries forward those formations, and then is lodged into the faculty of intention, which creates the intention behind acting, behind behaving, behind speaking, and behind thinking or reflecting.
And then you have what is the process of contact, which is happening through the faculty of contact, within mentality. The process of contact is the stimulation that occurs when the outside world meets with the six sense bases. This happens through the faculty of contact and mentality. Attention, manasikara, is what you're using for mindfulness, to be able to collect the mind towards an object and unify it around it. Attention doesn’t control but is able to perceive and understand whether to take any of these other four factors of mentality, and their processes, as permanent or impermanent, impersonal or personal, or worth holding on to or not worth holding on to.