How can I add gearing (shifting) system into the new roblox car chassis?

How can I add gearing (shifting) system into the new roblox car chassis?

I want to make a car game that surprise surprise needs gear shifting in the base roblox car system (The new one from the template).

I tried multiple things and I even looked into the Dev forum but I couldnt find anything related.
I even tried it myself but I couldnt really catch it as i am not a scriper.

Hope someone has the answer for me!