This is a low poly design of my own car.
The kitcar is based on a 2cv chassis.
I used 0.25 layer with a 0.4 nozzle.
8 top fills to prevent sagging.
Placing the axle
The axle can be pushed in the slots. I maybe necessary to make the entry a little wider.
Don't carve to much in the middle. Start cutting the corner of the slot. when this fits, push the axle just in.
Made this model in sketch up.