Firstly, pls clarify whether your car gear shifter goes, P,R,N,D,S or ,P,R,N,D,D3,2,1
To begin with, according to what I know the Reborn gear goes like this from top to bottom; P, R, N, D, D3, 2, 1.
D3 is same as D and is meant to be automatic mode except it uses the first 3 gears ONLY and basically is like a sport mode sort of, or when u need more power such as on hilly terrain, etc.
There is no D2, or D1 in reborn its only D and D3.
The number 2, and 1 displayed on meter and gear shifter are meant to represent the Second gear and First Gear, respectively. When car is put into 2 it is supposed to stay in Second gear only. The same goes for 1, and the car will stay in first gear until you change gear.